The time signature is the numbers - tell you how many beats per measure there can be and which note gets the beat. For example 3/4 time would be three beats per measure (top number tells us this) and the quarter note gets the beat (bottom note tells us this). For 3/8 time - we still have 3 beats per measures (again, top note tells us this) but the eighth note is the one getting the beat (bottom note tells us this).

The Key signature is in the same place - those are the sharps and flats telling you what key you are in.