boat repairs

Hi guy i have been offered a boat from a friend of mine for free and was wondering how hard easy is it to repair a dent in her shes around 21 feet fiberglass and something was dropped on her from a height and bellyied out the fiberglass about 4 inches from its true plane,most of the timer needs changing buts thats a handy job for me keel seems fine do i need to store it inside for fiberglass work ? thanks guys.

working with fibreglass needs to be done outside when its dry and because its well ventilated, just as long as you can store it somewhere dry when not working on it you should be grand, if you want help with anything

(did a fair bit of fibreglass work yrs ago, if you start getting dizzy, stop immediately and take a break from it)

When I fixed up my boat I left it at the side of my house and bought a huge cheap tarp attached it to the side of my house and over my boat giving me a sheltered outdoor work space.
Ventilation is very important.
That whole should be easy to fix... Can you post a picture?
Possibly some stringers or ribs could have been damaged also if something fell on it?