Midiguitar new instruments not recognized

I am new to all of this- I was able to donload and activate MG2 . I also downloaded o other instruments in a vst file. I have run the scan and the new instruments show in a folder. But I am unable to select them to use. Once I get to the track, how do I get mg3 to selct and save the instrument I want to use.

in mg3, click on an empty slot and select instruments. your vst’s should appear there, grouped by vendor.

it’s almost the same in mg2 if i remember correctly.