I have an anet a8 with an MKS Gen 1.4 Mainboard and MKS TFT LCD also with 8825 Drivers.
Having a few problems trying to get it to run. I can move the motors 1 way only. Recc optimal voltage for 8825 unable to measure the amps as i do not have a multimeter with Amps.
Motors are Busheng Stepper motors
Drivers are 8825
External MOS Fet Controller for HB
External Driver adapter for 2nd Z Axis
Power Supply is ATX Silencer 425w

You don't measure current to set stepper current, you measure the beef on thenstepper driver. There are pages on the reprap wiki that explain it.

Motors moving one way is associated with the end stops not being correct. Obviously it wouldn't affect the extruder.
If the controller thinks the end stops are activated it will only allow you to move the motors away from the end stops. This normally indicates its the state of the switches that's incorrect not the position of the switches.
End stops characteristics are defined in the config.h file so should be already in preinstalled firmware for your machine. If the switches are not connected they should default to activated to protect the machine. So check the switches are connected.
I think you send the M119 command to get the end stop status.