Do squats. Until you think you are gonna break (but use good form). They are a mass builder.

Squats, Bench Press, Pullups, Deadlift

If you are looking to add mass to your frame, those are the only lifts you want to be concerned with.

Drop cardio to 3x per week, after weights. Not on Squat day though. Or Deadlift day either.

If you did 4 hard sets of these (after warm-ups sets of course) in each workout ... and each lift as it's own workout ... and had a good meal replacement as a post workout drink I can almost ASSURE you of lean mass gains.