How to change buttons in Razer Synapse

I have a razer naga trinity, I'm trying to set a back and a forward button up on my mouse but I can't find the options for those anywhere. I've saw quite a few posts saying to add macros but I don't have any options for that in synapse. So I'm kind of lost and frustrated, I've went through the software multiple times and the closest thing I could do was assign a button as backspace. Which would go back a page sometimes not always. But I had nothing to go forward a page. Any help would be greatly appreciated.