I'm 21yrs old I want to start working out routine circuits but I don't want to lose weight im 95lbs. I want to gain an build muscle. Needs suggestions?

Increase calories . Building muscle while maintaing weight begins with increasing calories and hydration. You may want to think about adding protein supplements to your daily diet when you work out. Start with muscle building exercises with light weights. Standard exercises like push-ups and sit-ups also build muscle and are good beginning exercises. Hope this helps, if so, please vote or follow me, thanks!