Im trying to make a GUI rise from the bottom of the screen when you press "f" but don't have an idea how to pull it off
You would need to start on How to use UDIM2 which can resize or position a GUI. Also once you mastered UDIM2 Tweening a gui would be most beneficiary for you, also learning KeyDown Event may make this all possible for you.
Tweening a gui is just like UDim2, In Tweening you can change the size and position of the gui , and a little extra.
+1 if this helped :)
Try wiki.
You will need to change the GUI's Position property with UDim2.
http://wiki.roblox.com/index.php?title=UDim2