Active job

Plasterboard and insulating a garage

I have a garage at my house that I would like to plasterboard (see attached), as well as insulate the roof. It currently has an internal wooden frame to work from. There are some windows to work around which will remain. And there is an internal door which I may also look to keep or replace but would like some advice around this. I have had an electrician in recently who has added extra sockets and lights which he will complete once the plasterboard is up. I would also like to add two shelves at the end. From conversations with a previous builder I suspect it is a two or three day job. I am flexible for weekday or weekend, and can be anytime over the next month or so.