Exercise/Work out advice?

1st of all, im a skinny guy. not very skinny, just scrawny. anywho, i need help on this stuff. for example, on sunday i did push-ups. i did them (not fast or slow, just normal pace) until i could lift myself up no more. i stopped at around the 30s. i took a break and did another set. the next day my chest & triceps got sore(means i did it correctly). the next day i did ab exercises. i woke up the next day with sore abs. so far getting sore muscles means i did a good workout, but im confused. do i have to wait until my muscles are not sore anymore or is it ok to do the same workout the day after? im worried that if i do the same workouts while those muscles are sore, i wont get results. right now my abs show. just not much because i have to do this often. what i want to know is when i work out a certain part (example arms), how long do i wait till i work arms again? and the same for abs, legs, shoulder, back, etc. i dont want to waste money on the gym. i want to do this myself.