what kind oh exercises can i start doing in home?

You can do many exercises.  There are many shows on cable TV that also will help you if you want to follow their routine and need motivation.  Squats, push ups, situps, leg lifts, and lunges are a few.  If you have dumbbells you can add a lot more.  The dumbbells will also help get you a better workout in a shorter time.

The only bad exercise is no exercise.  Are you trying to lose weight?

why u want to do exercise

first thank's for the answer no, i'm trying to get muscles couse i'm very thin. but i don't know how to start...