You could try to move it from a terminal window (repetier host, pronterface, etc.). That could help to isolate the problem to either the LCD screen or the controller.
You could also get out of Marlin Mode (hold the round knob for a few seconds) and see if you get the same error in Touch Mode.
It may be an issue with the cables between the LCD and the Controller not connected correctly.
Can you please post pictures of the control board showing the side with the motor cables connected to the board, as well as showing the underside of the LCD screen.
I would like to verify that the cables are not attached incorrectly, and that the JST housings have been removed.
Does one cable go from the SKR to the motor? Did you have to join some to get them to reach? if you did can you show us that? and where the cable attaches to the motor, Sorry don’t mean to be asking for so many photos.
The motor you went with is a little weaker than the motor recommended by @vicious1 (He recommends around 84oz-in steppers. The ones you got are about 54oz-in) This should NOT cause the issue you are having, the limitation you will have is your LR3 wont be as strong or as fast (however we hardly reach these maximums anyway)
Before you send more photos, do try to move the steppers again but with the lose purple and white wire pulled away from the board.
So the pictures clear up some questions, but raise others.
Your black cable from the display to the controller looks to be oriented correctly, but I suspect that it is not making contact correctly on the controller end due to the black JST connector on the board (not compatible with the DuPont connector on the cable). I had the same issue with my build, and had to remove the black plastic part from the controller board. This may be why you are getting the “printer not found “ message. All of the other cables between the LCD Display and the Controller seem to be correct, at least as far as the connectors go. I can’t see if you have the EXP1 and EXP2 cables crossed between the two boards or not, but if you followed the documentation properly, then hopefully that is good.
As far as the motors not working, there may be a few reasons, but it is hard to diagnose this without more info.
It appears that you bought most of your parts from someone other than Ryan, which makes me wonder whether the board is flashed with the correct firmware. Perhaps you could post a screenshot of the firmware on the starting screen.
It might also be helpful if you tried some simple g-code commands through the controller USB port (for example G0 X1 to move the X axis 1mm in the positive direction) to see if it is a LCD Display issue (be careful moving the Z or Y axis more than a few mm at a time, as if one motor is reversed, it will rip the build apart)
Your motor cables all have JST connectors, , so they are compatible with the JST connectors on the board, so you shouldn’t need to remove anything there. Note that you will probably have to reverse some wires once you get things moving, which will require retracting the pins in the cable connectors (the DuPont connector supplied by Ryan is easier to reverse, as you simply rotate the cable and connect it backwards, but that requires removing the plastic JST connector from the board as well).