Exercise at home without going to the gym

I'm not fat or anything just quite skinny though I want to get extra muscle and maybe a six pack, I can never get into a proper workout, I do it for a week and then stop, what can I do to build muscle? And how can I keep my work outs at a daily pace?
I...

haven't exercised for like a month and a bit now. I'm 15 years old. Pls help on some workouts I can try. I have access to everything apart from the gym.
Thanks a lot.

U could get those workout videos.

Go out and buy 1 thing...a yoga ball, a big rubber/plastic ball that you sit on...Do abs about 2x-3x a week and do about 12-15 sets total. Pretty much just to situps on it to work the upper abs. brace your feet on the wall sidways to do obliques and turn over to work your lower back. To work lower abs do leg lifts on the floor. Look on youtube or see the exercises for yourself. Make sure you aren't doing them make and if you can't feel it you're not doing it right. Go slow and do about 10-15 reps everytime.