I could give you a couple of tips but what you want to work or your goals?
Well if you to be completely fit and a flat stomach. You need a routine workout at least 4 times per week. If you are just starting to workout I recommend 6 times per week. I know that's one day off but you need results. There's a lot of workout on here but you should start with "Power Challenge" search it in the workout section. Its kinda intense if you just starting out. You could do the push up on your knees of u want but I don't recommended. Combine Power Challenge with Abs/core intense workout. For absolute result make the schedule like this Monday/Tuesday =workout HIT Wednesday =day off Thursday/ Friday = workout HIT Saturday = do like abs,yoga,cardio Sunday =day off. Keep that routine don't get lazy and get tons of sleep eat healthy stay away from Trans Fat.