Can someone help me make this?

[MahdyE23]

Ok. So, I want to make it so when people go to my forums, the first thing they will go to is a TOS page.

What I mean is this:
When they type in my website, it will redirect them to www.websitehere.com/tos with a custom TOS page. I want to add one, I just do not know how. I also want to make it so they have to type in a little box "I agree" and then they can be redirected to the forums.

Questions:
-How would I custom make one? Could I just make one with simple coding? Although I don't know much, I think I can find a website that can help me customize it better?
-Would I edit the index.html file in my FTP files, or would I make a new page in the forums directory called tos or something similar?

If you do not understand what I mean I will be happy to explain it in any other way that I can.