Five days of inaugural fes-tivities ignited Wednesday with fireworks - literally - and a flag-waving, foot-stomping, star-spangled, all-American-style celebration of freedom, one in which several Utahns had central roles.President-elect George Bush used the opening ceremonies at the Lincoln Memorial to set the theme for the next several days - "Let this inauguration be a time to celebrate who we are, and let it also be a time to remember who we can be."

Bush said that means reveling in the diversity among Americans, in the strength that brings and in how it creates a beacon of freedom and hope to the world.

He said that during his campaign, "I tried to explain my vision of America's greatness. I described America as a nation of communities. And I said that the American people represent a brilliant diversity spread like stars, like a thousand points of light in a broad and peaceful sky."

To represent that thousand points of light, Bush lit an Olympic-style torch while 40,000 people in the audience waved flashlights given to them. That was followed by a thousand seconds of light through fireworks - a massive display launched at the Washington Monument.

Bush spoke Thursday of his optimism about the future but also expressed his feeling that President Reagan's "shoes are going to be pretty darn hard to fill."

The president-elect told a group of top high school students his mission was "to help build a better America," and he appealed for their help. "I really feel this: Our best days are yet to come."

The president-elect spent most of the day out of the public eye until the inaugual gala.

Reagan, for his part, said Thursday that he is leaving office "without a hint or a clue" as to the whereabouts of Americans held hostage in Lebanon.

In a farewell interview with news service reporters, Reagan said that while he feels bad about the hostages, the situation should not be likened to the one when he came to office eight years ago. Fifty-two Americans held in Tehran were released on Jan. 20, 1981 - the same day that Reagan was inaugurated and President Carter left. Reagan had harshly criticized Carter during the 1980 campaign for failing to win the hostages' release.

Meanwhile, Barbara Bush, the president-elect's wife, won cheers and laughter Thursday from audiences that packed three theater halls to hear her joke about her appearance and her husband's fishing.

Mrs. Bush stepped out from behind one lectern and told her audience, "Please notice - hairdo, makeup, designer dress. Look at me good this week. And remember. You may never see it again."

She also made fun of her husband's comments on how tough it has been for him to pack for the move to the White House. Noting he spent two days fishing last week in Florida, Mrs. Bush said, "So much for the packing story."

More exuberant portions of opening ceremonies featured a 21 "Top Gun" salute with 21 Navy fighters and bombers flying over in wing-tip-to-wing-tip formation, plus Army parachuters and an elaborate military presentation of the colors.

It also included a wide range of American music, including the country singing Gatlin Brothers and Lee Greenwood, gospel singer Sandy Patty and the Beach Boys _ who had the Bush's grandchildren bopping and hopping on stage.

The Jets, a rock group consisting of seven of 15 children of the Wolfgramm family that once lived in Salt Lake City, also performed. They are members of The Church of Jesus Christ of Latter-day Saints, and were among clean-cut groups chosen to represent America's youth. Bush thanked The Jets personally for performing.

Bush said banquet hopping _ and personally greeting as many of the guests as possible _ was "an exhausting, inhumane procedure."

Protesters outside one banquet site fed 1,000 homeless people for the cost of a $1,500 banquet ticket. Utahn Steve Studdert defended the cost of the banquets, saying they were meant to raise money for other free-admission inaugural events.

Most guests at the expensive banquets were surprised to find that their $1,500 did not give them a reserved seat. Alan Collier, Salt Lake City, was among those quoted in Thursday's Washington Post criticizing the situation where the non-elite were told to sit at any table not marked by a reserved sign.

"So we found a table and sat down and then all of the sudden someone came over and stuck a reserve sign on it. Then we found another table and it happened again. That would never happen in Salt Lake City. I guess this is the big time," Collier told the Post.

The Mormon Tabernacle Choir had a quick sound check Thursday morning at the Capitol, where it will provide prelude music for Bush's Friday noon swearing-in ceremony.

Also, the choir performed Thursday afternoon at a dress rehearsal for the Inaugural Gala _ a rehearsal witnessed by an estimated 10,000 people in the Washington Convention Center.

The actual performance of the gala was carried live by CBS Thursday night.