New carpets

I have a spare bedroom that has a very heavy (a sort of melamine but good quality and with a sliding door because the room is so small) wardrobe with a matching desk and bookshelf and a horrible IKEA bed that I bought by mistake not realising how huge and heavy it was. Under which is stored years and years of heaven knows what. And annoyingly it’s all on a very cheap carpet which, for some unknown reason, has no underlay. I’d love to turn it into a nice bedroom and sleep there myself as it overlooks the back garden. But I just don’t know where to start with it .