connect a gateway/npqsql

Hello everyone! I am asking for serious help, I need to install the npsql to allow for my postgresql database to connect via a on-prem data gateway to Power Apps. I am not a coder, I do understand very basic things and can make things work around, I even downloaded visual studio and could download it. The problem is it doesnt kind of execute, so like its installed but not really, I need to set the parameters to GAC so that I can make the connection work. Videos on youtube are pathetic and the documentation on the sites of postgresql and nuget are not enoigh for me to wrap my head around. Please send help :) Thank you!