You are going to the beach. What items will you take with you?
When I go to the beach harbor only a towel, because when I go on holiday I only beaches to relax.
When I go to harbor beach, I just take a towel. Because when I go on holiday I only go to beaches to relax.
When I go to the beach, harbor I take only a towel, because when I go on holiday, I only go to beaches to relax.
And what about swimming? ;-)
N.B. After the "when-clause" you have to write a comma.
When I go to the beach (harbor) I only take \ have a towel, because when I am on holiday \ ..when i am on a summer break (vacation) \ I only visit beaches to relax. \ ..I only want to relax.
I hope you don't forget the swimming trunks, except "only towel".. :) and you should have also some lotion to protect your skin from the sunburn!
Buona fortuna! ;)