The Ugandan capital returned to a semblance of normal today as its citizens showed up at work for the first time since Field Marshal Idi Amin's reign of terror ended here a week ago.

Provisional President Yusufu Lule held his first working Cabinet session since the new government returned from exile in the wake of the Tanzanian-led captujre of Kampala.

Communications Minister Akena Pojok said the Tanzanian troops sieixed a key installatioon, the huge Owen Falll Dam on nthe Nile River near Jinja before the feared sabotage by Ugandan troops loyal to Amin. The power station provides Uganda and parts of neighboring Kenya with electricity.

Officials said the advancing Tanzanian troops had not yet taken the nearby industrial center of Jinga, Uganda's second largest city, where the missing Amin had once vowed to make his last stand.

In Kampala, women employes of the city council used brooms and leafy branches to sweep up the broken glass and litter left by the orgy of looting that followed Amin's downfall.

Answering the provisional government's return-to-work call after the long Easter weekend, public and private sector employes ventured into the city center for the first time enmasse in private cars, city buses and on foot.

The extend of the new authorities' problems was illustrated by the gutted shops and ransacked government offices manned by employes who had little to do except clear up the looters' mess.

A visit to the Commerce Ministry found the minister's secretary on hands and knees picking through documents in a large office bereft of a single chair, working telephone or typewriter.

The new minister, who replaced the Amin appointee described by the secretary as "no loss," has yet to return from abroad.

In a search for the person in charge, an articulate man-asked if he was the top civil servant in the ministry-replied, "I used to be," as if to suggest that his future status was far from clear.

Feeding such uneasiness was a statement by Defense Minister Yoweri Museveni in the first issue of the Uganda Times, which replaced Amin's Voice of Uganda newspaper.

Although the first editiorial said, "Those who delight in revenge are as dangerous to the efforts of the revolution as those who sabotage the reconstruction work," Museveni called on the public to turn in "agents and collaborators of Amin's regime of death and misery" in "the national interest."

In looted shops along the main Kampala Road shopping district, store owners tidied up the totally gutted premises.

Mike Kagwa of the K.D. Department Stores,specializing in clothing and books, summed up a general mood among shopkeepers when he said: "We're just waiting to see what the government is going to do for us."

A man speaking in the commerce minster's name addressed a thousand or so civil servants and business people on the steps of Parliament and asked them to "mobilize yourselves."

He said, "This town is a ghost town, an empty town, but it is empty because of what you know, because of the change which you all welcome. From now on go back to your shops and industries and try to do what you can."

The new authorities are trying to get the economy back on its feet after eight years under Amin. The vital economic lifeline of the landlocked nation, the road to the Kenyan border, had yet to reopen. It runs through Jinja, 50 miles east of here.

A few more policemen, in starched khaki uniforms, are seen checking car registration and identity papers, tasks hitherto performed in offhand fashion by Tanzanian and Uganda exile troops.

The head operator said in the presence of her full complement of long-distance and overseas-call operators, "At least coming in today reassured us that we were all alive." But telephone and telex communications outside the capital and with the restof the world remained cut for the third successive day. CAPTION: Map, no caption, By Richard Furno-The Washington Post