Before you can transform a space, you have to get rid of whatever's in it. As you clean, sort things into three piles: toss, donate/sell and keep. If you have enough in the donate/sell pile, you could host a yard sale or use community groups like Facebook Marketplace to rehome your old things. Redistribute your keep items throughout your house, or set them aside if they'll work in the room's new role. Toss anything that doesn't make the cut for either of those two piles!