Need help exercising / building muscle

Olivia🧚🏼‍♀️ • NYC living 🤍 🗽 22🥂🫶🏽

Long story short, I was in the army and now I’m not. I was medically discharged. I want to go back and finish so badly. I’m wanting to go back part time (reserves/NG) because I want to keep my full time civilian job and I also want to go back to college. Anyway, since I’ve been home I’ve gained A LOT of weight. 30 pounds to be specific. I’m having my thyroid checked as my PCP believes that was the cause. Purpose of this post is to ask for help. I need to know what kind of exercises I should be doing, whether at home or the gym, to get strong, build muscle, and lose the weight I gained. I want to go back as fit as possible but I don’t know where to begin. If anyone can comment a simplified version of their muscle building workout routine I would really appreciate that