[JFreak]

Hi, welcome to the community.

Don't get confused about the menu. The difference of a plugin and i/o is that from the plugin list you choose the RTAS software plugin you wish to use, and from i/o you obviously choose the hardware insert you wish to use for connecting your outboard hardware. No insert means if you have something in the slot you can get rid of it.

Difference between multimono and multichannel is that if you for example have a stereo track and want to use a stereo compressor, the multichannel version works the same way for both channels whereas multimono you can have different settings for left and right.