President Reagan's undeclared campaign for a second term moved forward significantly yesterday at meetings both inside and away from the White House in which Reagan and some of his chief advisers were told that the basic decisions on political organization for 1984 have been made.

"If you're going to wait until November or December to go, you've got to be ready when you do go," said White House chief of staff James A. Baker III, who met for 20 minutes with Reagan and Sen. Paul Laxalt (R-Nev.) in the Oval Office to discuss campaign plans.

Both Laxalt and Baker said after the meeting that they had "no doubts" that Reagan will run, even though he told them he has not made up his mind. A meeting of Reagan strategists later in the day in Laxalt's Senate office proceeded on the assumption that the president will be a candidate, as did a White House luncheon attended by Laxalt, Baker, deputy White House chief of staff Michael K. Deaver and Republican National Chairman Frank J. Fahrenkopf.

At least three White House groups are trying to put a practical political stamp on such key issues as education, the economy, the environment and civil rights. One adviser said that about a dozen Reagan activists already have been informed that they will manage state campaign organizations eventually.

"I've been told he's running and that I'll be in charge of the Florida campaign," said Panama City auto dealer L.E. (Tommy) Thomas, a longtime Reagan organizer.

These developments came on a day of heavy political activity for Reagan in which he touched on prospective campaign issues while trying to divert attention from the controversy over how Carter White House documents wound up in the possession of his 1980 campaign staff.

Yesterday, Reagan awarded a presidential medal for heroism, gave a pep talk to distinguished teachers, met with congresswomen to discuss a legislative agenda for women and celebrated the economic recovery after a meeting with Chrysler Corp. Chairman Lee Iacocca.

Reagan made no public comment about the briefing-book controversy, but Laxalt quoted him as opening the meeting by saying that Baker's job is "secure" and adding, "Convey to your colleagues that no one in the White House is twisting in the wind."

This was the message that Laxalt carried later to a meeting of a dozen campaign advisers in his office. Among those attending was Warner Amex Chairman Drew Lewis, the former secretary of Transportation who reportedly is scheduled to be the Reagan campaign manager in 1984.

The White House has now entered what one official called "a reelection mode" in which every issue is addressed for political impact as well as substance. Another official said that this approach has been characteristic of the Reagan White House but has intensified in recent weeks as it has become apparent that the president will seek another term.

Still another official joked about the heavy political emphasis, saying, "Elections focus the mind wonderfully."

Three White House groups, some with subcommittees, have reportedly been responsible for much of the issues focus. One, which meets every two weeks and is chaired by Baker, is known as the "outreach strategy group" and emphasizes issues involving specific constituencies, such as women and members of minority groups.

Two other groups that play a major role in shaping political policy development are chaired by Deaver.

One is an informal luncheon group of senior advisers where strategic ideas are presented. The other is the formal scheduling group, which chooses presidential events aimed at winning over key constituencies.

In the past several weeks, both groups have been trying to find an appropriate stage for Reagan to express his empathy with the blue-collar workers who were an important segment of his winning coalition in 1980. Yesterday, the White House announced that the president will fly to Florida Monday to address the International Longshoreman's Association.

But not all issues development in the White House is part of a pre-conceived political offensive.

"Much of it is reactive in response to events we have to face whether we want to or not," one official said.

This official said that this week's "civil-rights offensive," in which Reagan used his weekly radio speech to emphasize previously announced housing proposals, was determined by the Senate confirmation hearings on the president's controversial appointments to the U.S. Civil Rights Commission.

This issues emphasis is expected to continue throughout the summer, though no campaign organization is likely to be formed officially before mid-October. Baker and Laxalt say they expect Reagan to make his formal announcement in December, after his trip to five Far Eastern nations.

However, the people who will staff the campaign organization already have been designated.

Laxalt will serve as the overall chairman with Ed Rollins, now the White House political adviser, moving over to become political director. Rollins' deputy, Lee Atwater, will continue in the same position at the new committee.

Laxalt said that Angela (Bay) Buchanan, the 1980 Reagan campaign treasurer, will be treasurer again in 1984, and that Boston attorney Roger Allan Moore will be campaign counsel. Washington political consultant William Timmons has been designated to manage the Republican National Convention.

The process of picking the Reagan chairman for each state is less advanced. One member of the Reagan team said yesterday that "a lot of responsibility will be given to incumbent Republican governors."

He named George Deukmejian of California, Richard L. Thornburgh of Pennsylvania, Thomas Kean of New Jersey and James R. Thompson of Illinois as examples of GOP governors who will be given heavy responsibility by the White House.

Selection of the state chairmen was described by one Republican involved as "a delicate process" because the campaign organization is relying on longtime Reaganites in some states while trying in others to broaden the campaign's base by bringing in Republicans from outside the Reagan organization.

Most of those involved in this process are proceeding on Laxalt's premise that the president is certain to be a candidate. While there are still a few doubters, pushing the announcement back to December would make it difficult for the Republican Party to shift gears to back another candidate if Reagan decides not to run.

In that event, now considered remote, Republican professionals believe that Vice President Bush would have a heavy advantage over anyone else to get the Republican nomination because of the short time that would remain before the 1984 primaries.