Best home workout routine?

I have been doing my own home workout routine for the last 2 months for about 4 days a week but I am wanting to know what different or better techniques I can use to bulk up faster. I am only 60kg (132lbs) and I am 172cm in height, I am also 18 years old. I feel as though I am too skinny and look too weak so I would like to bulk up a bit, so please don't laugh at my workout routine as like I said, I do think I am fairly weak. I am wanting to work on my pecs, thighs, abs and biceps, but I do not want to go to the gym, I would just like to workout at home. My current routine is 80 15kg dumbell reps on each arm (split up into 20's on each arm), 200 cross armed sit-ups (split up into 100) and 40 lunges on each leg (split up into 20's, I know that isn't much but my legs are really weak). I currently don't have a pec building routine but I would like to start one, I just don't know what techniques would work best at home. I don't really have any equipment, all I have is a sit-up mat and dumbbells and weights.