Testing Axes before completion

I just put in my stepper drivers and downloaded Marlin, I wired in the steppers and that is it. At this point without anything but the stepper connected how can I test them before I move on? I have Cura on my computer and an lcd screen wired into my RAMPS. I can't figure out how to get the lcd working though, when I turn on the power supply all the lcd does is turn on but nothing on the screen though. The only reason I wired the lcd in is because I thought I could use it it test the axes. I'm totally new to all this firmware stuff so I'm sure I made a million mistakes. The building part was easy, but now the computer part is really getting to me....
Thanks!

Just about any host program should give you a widget where you can enter G code interactively. You can try moving around a bit with the G1 command. First do a G90 to set absolute positioning, then try G1 X10 F1000 for example to move the X axis to position 10.

You can also move axis Y and axis Z this way (Axis E - the extruder - too, but there are some additonal considerations there) You will only be able to move in a positive direction until you home. You can home everything at once with G28, or you can home one axis at a time: G28 X0 for example. Be aware that homing will use your endstops, so if you do not have them in place, you may have a crash.

Here is a nice G code reference.