Hi guys! I'm pretty new to fitness and I want to finally get in shape. I'm in my late 20's, 5'7", about 125-130 pounds (haven't weighed myself recently). I was always naturally thin, ate what I wanted and never exercised. I want to build muscle and improve my energy and mental health. I have been lurking in fitness subreddits but I still had some questions.

I'm think of doing the Strong Curves program and I just bought the book. I know my main focus should be lifting heavy, but should I add in cardio (walking on a treadmill on an incline) a couple days a week too? Would adding in walks or yoga help?

Also, I think I should be eating at a calorie surplus. I'm planning on eating around 2000-2100 calories so I can start gaining weight and fuel my workouts. I'm also using MyFitnessPal to track my macros (focused on protein). I'm not used to eating this much. Should I focus on calorie surplus or maintenance when building muscle?

Any others tips you have would be awesome for a newbie like myself. I don't have a gym right now besides a treadmill and some dumbbells since I'm in the process of moving so I'm might focus on bodyweight exercises for now.