Open OBS.
Go to the Tools menu at the top.
Auto-Configuration Wizard.
Beyond that, there are no 'best settings'; it comes down to trial and error to see what your system can handle.
Unfortunately, AMD's AMF hardware encoder is absolutely godawful. Uses rendering resources for encoding tasks (NVENC does not), produces terrible quality encoding, misreports feature levels, and can easily break on driver updates. Would recommend sticking to x264 Software, even if it's a significant load on the CPU.