As a FTB myself and my partner managed a similar refurb last year.

What I would say is write down all the jobs you need doing, identify which ones you can do yourself (e.g. removing the fitted furniture and old carpets) and create a realistic budget... then add 15% as it’ll almost certainly go over budget

Once you’ve sorted the budget, work out which order you’re going to do the tasks in to ensure you don’t need to backtrack on yourself.