A nationwide audience on ABC-TV Thursday night saw the first Reagan-for-president commercial of the fall campaign, a five-minute spot in which Reagan summarizes his approach to economic policy.

The commerical ran in an expensive time slot at 10:55 p.m. at the end of the popular magazine show "20/20." It was the first spot made for Reagan by his new media adviser, Peter Dailey, a West Coast advertising man who did commercials for Richard M. Nixon in 1972.

Before the campaign is over, the Reagan and Carter camps will spend more than $15 million each on television commercials. At the moment, John B. Anderson's independent presidential campaign lacks sufficient funds for a serious national advertising campaign.

The spot that was broadcast Thursday night began with "man-on-the-street" interviews with people affected by the recession and inflation, then switched to Reagan in a book-lined study. The bulk of the spot consisted of the candidate giving a brief speech on his optimistic economic plans.

The major issue, Reagan said, is "more jobs for Americans," and he promised that they can be created: "We'll do it by allowing America's economic system to do what it does best -- expand, produce some more, expand some more, and at every step of the way create new jobs. . . ."

The spot ended with a new slogan: "The Time is Now for Reagan."