Can someone answer the following.

I have an existing bonus room above our garage that was not completly finished when we bought our house. The builder was trying to unload the house so we opted to let them leave the bonus room as-is and save money on the house price. The room was framed out, completly wired, and the HVAC ducts capped off but not ran and vents not installed in the walls. So here is my questions.

Do we need permits for the following.....

1. Put in the insulation (some insulation was already put on the walls)
2. Sheetrock the walls
3. Run duct work and install vents. (duct work already there, just capped off)

Last, Can I do the work myself, as a homeowner. I know how to do all the above.

Thanks