Lost power in half the house. There is a double braker with a red wire and a black wire when hooked up restores power to that part of the house but all lights are dim. What do I have to do to regain total power.

You may have lost a neutral, are some dim and some bright or blown? Does 240 volt central air work?
I would verify 120 between both hots to neutral and 240 volts out of 240 volt breakers.