Let me try to help you out here Lexic,
You will need to go to a site that lets you have free hosting, for example I use forumotion.com, you register with them and then you set up a password and such as the admin. Once you have done this you can then give the login details to the person who is going to help you out, they can then have access to your control panel and sort out all the layout and details that you are asking them to do. Once the set up is done you can change your login details or password to make it only know to you again. Because you are registering the new forum in your name and your details once the forum is set up you will still be the full owner of the site......If the person helping you out does all this they will officially be the owner because they entered all their own personal details.
I would suggest you read up a bit on all the details of how to set up a site first if this part is already a bit confusing as you may struggle later on once it's handed back to you.
On a side note, I notice that basic manners are a bit lacking in this thread, it would be more beneficial if a few please and thank you's were included, people respect you better. I'm only trying to help here :great: