Republican National Convention officials said Friday their $15 million makeover of the Louisiana Superdome is already about 20 percent complete just five days after they took over the massive arena to prepare for next month's convention. ``We are on schedule or ahead of schedule on every phase,'' convention manager Bill Phillips told reporters during a guided tour of the dome. Work was being done on the framework of a huge, $570,000 podium from which President Reagan, Vice President Bush and other dignitaries will adress the 31,000 people expected to attend the convention, which runs Aug. 15-18. Phillips said the Republican Party is spending about $9 million on the convention. The city of New Orleans is raising about $5.5 million through private contributions to pay for the sound and light systems and other projects. ``Basically, we're looking at a $15 million operation,'' Phillips said. Best known as an indoor football stadium, the dome is looking less and less like the home of the New Orleans Saints and more and more like a media center. Four television networks will have tall, multi-level booths near the podium. Carpenters and electricians worked to convert suites known as skyboxes, which overlook the floor from the perimeter of the stadium, into broadcast booths for other radio and television broadcasters. Arising on either side of the podium was the framework for the structures from which print journalists will observe the proceedings. Still to come is the hanging of the nine-story high, three-ton blue curtain that will serve as a room divider for the dome. Public convention business will be conducted for the cameras on one side while trailers, used as offices, will be driven onto the floor behind the curtains. Phillips said construction should be completed by Aug. 10, giving convention officials plenty of time to run tests on equipment before the convention begins. Once the convention ends, the construction work begins again _ in reverse. The Republicans' agreement with the Superdome calls for the stadium to be restored to its original condition by Aug. 25.