guitar amp vst plugins issue

Hey there,
i’m new to this forum and to cubase. I’ve got elements 8, evaluation version, and i can’t do what i’m seeing on the tutorials on youtube regarding the vst plugins. I can record via a mic but if i plug my guitar in the sound card, i hear the guitar, ok, but i can’t get the interface to change the sound. I downloaded a free plugin, intalled it and i can’t see it in the list. And if i choose an virtual amp, i always see a synthetiser interface where playing with the knobs don’t do anything to the sound.
I’m lost…
Thanks for the help…

I know now that elements does not allow for external plugins, but i just can’ use internal plugins, so for this one VST Amp Rack should work with elements, and i can’t find it.
How do you do to load a vst plugins ?
Thanks for any help