From the "Edit" menu, choose Define Variables...
I clicked the "Create" button and created a variable called Jim1.
My choices are Logic, Number, or Text... I choose Number.
I drop a VARIABLE block onto the desktop... the configuration menu allows me to select Jim1 as my variable.
Then I drop in a MOVE block... I "wire" the Jim1 variable to feed into the Power port.
Most blocks have these drop-down wiring ports... left side is input, right side is output... using these, you can use the actual values from blocks (and your own defined variables) to feed values directly into other blocks...