Resources on exercises?

Basically I talked to a counsellor and since I can't really start properly transitioning until I move out hopefully next year (because of parents and stuff) she recommended that I do some research on HRT, maybe do some exercises to get my body in a way I was happy with, get a job etc. What I'm asking about here is the exercise part. I'm 6'1/6'2 (can't remember since I last measured) at 17 and quite stocky, I'm also... Tubbier than I want to be? So I really want to slim down and get my body way more feminine, ideally with exercises I can do in my room, and I have two small dumbbells with adjustable weight. Other than that I can go for walks, but that's basically the extent of the freedoms I have when it comes to working out. If you knew any links to workout guides or just general workout advise so I could prime(???) my body for when I am able to take HRT that would be 1000000000% appreciated. Also, any advise on sticking to a workout routine because that's what I struggle with the most since it is a lot of effort and I've never stuck it out enough to see results and keep me motivated. Tyty.