After I connect my MIDI keyboard to my laptop and i have Audiotool open, how do i plug in sounds and play them from my keyboard so i can add them to the song i'd be making?
You don't "plug in" sounds. Your midi controller is just that- a controller so you can trigger sounds from your DAW without having to click on anything with your mouse.
In Next: Right click on your device (or your device's knobs/faders if you want to make automations with your controller) > Learn Midi Controller > Play a key/pad on your midi controller then it should get recognized.
OG AT: Hover over to the wrench in the top right corner > Midi Setup > Setup Midi > Your controllers are displayed- hit Close > In Autolearn, click on any knob on your device then play a key on your controller and now your device should be linked with your controller.
lol