Hey @lil_zkyra, welcome to the Unreal community!
To add on to what @eldany.uy posted, you can also promote a value output to a variable directly from a blueprint node by dragging the output onto your event graph and choosing the option “Promote To Variable”. Functionally this is the same as creating the variable on the left and hooking up a Set node to your output. Remember that if you need your variable to be editable by other blueprints you must check the eye icon in the variable list on the left; a closed eye is private while an open eye is public.
I hope this information helps!