Where to go?

Question
I'm new at football and sometimes when I play tackle on the O-line in practice I find myself standing with no one to block. In a game situation would I just block a T.E?. If not how would I know whom to block.  

Answer
Daer New Guy,
I think you mean defensive end? Here is a simple rule you can follow. It is an out dated rule, but it is better than blocking nobody. Man, gap, and linebacker.

You start by blocking the man who is lined-up face to face with you.

If no one is face to face with you, block the man in the play-side gap.

If no one is in the play-side gap, go after the play-side linebacker.
Your friend, Coach Louis.