If only/only if

Hello every one.

How ‘‘only if’’ and ‘‘if only’’ are used in sentences?

Are these sentences correct?

Only if you don’t fight there,I can let you go with your friend.

If only I were there,I’d enjoy.

Only if you don’t fight there, can I let you go with your friend. – Though this is not a natural form of statement and would be better written: ‘I can only let you go with your friend if you don’t fight (there).’

If only I were there, I’d enjoy it.