I’m a bit of a newbie like you, but how I did it was within the Raspbian GUI, i launched it with the STARTX command, then inside there accessed the settings, and there was an option in there for wireless networks. I could cause it to search for the wireless network then typed the password in there. it didn’t give me a confirmation that it was connected, I just launched the internet browser and confirmed it was connected.
your PI does have a wifi adaptor in one of the USB slots doesn’t it? I don’t think there is such a thing as a PI that has on board wifi capability.
I hope this helps.