1. Hacking away old tiles.
2. Determine if you want hot water piping, either boiler type or instant type. You can use a mixer with boiler type.
3. Purchase the correct offset WC and a basin (cost which you can get yourself). Same goes with bath accessories like towel holder, mirrors, shower fittings.
4 Screed and waterproofing.
5. Change your window
6. Laying new tiles (tiles you can buy yourself and know the cost)
6. Change your ceiling.
7. If space permit, you can box up your pipes.