Yellow button indicates that your opener is Security+ 2.0. These models do not support a simple wall button option. Please see these posts for workaround. In the setup instructions this issue is mentioned as follows:
Some of the systems (notably security+ 2.0 openers) use encoded protocol for wall buttons. If there are no terminals for wired garage control button, then Garadget can be wired to the contacts of the button inside of the spare wireless remote.
Please don’t hesitate to post your questions if you need help with this process.