Home switch problem first time build 3D printer

1) My Repetier-Host software having problem with X and Y or Z when i click on "+50" it move to "back" and when i click on "-50" it move to front how can i invert this 2 signal? Like +50 it move to front , and -50 movie to back .

2) And also does anyone know how to setup the Home Direction for my 3d printer RAMPS 1.4? Because right now i click on Home they not run back to mid plan they run everywhere ( x ,y ,z axis ) wont stop. How can i setup the offset point for my 3D printer?

3) How much limited switch do I need on my 3d printer Ramps 1.4 and the proximity sensor is hard to install?

I'm the first time builder with 3D printer with RAMPS 1.4 please give me some advise or some tips to do it thanks everyone and have a nice day

Go to the Configuration.h file in Marlin, and edit this line:
#define INVERT_X_DIR true/false
Reverse the true/false that's in there right now.
For setting up the homing direction, in the same Configuration.h file, go to the following 3 lines:
#define X_HOME_DIR -1/1
#define Y_HOME_DIR -1/1
#define Z_HOME_DIR -1/1
and choose the direction you want, i.e. if you want homing to the negative X direction, leave the line as
#define X_HOME_DIR -1

so which mean is should entering my coding like the one u giving me?

Go to the Configuration.h file in Marlin, and edit this line:
#define INVERT_X_DIR true/false
Reverse the true/false that's in there right now.
For setting up the homing direction, in the same Configuration.h file, go to the following 3 lines:
#define X_HOME_DIR -1/1
#define Y_HOME_DIR -1/1
#define Z_HOME_DIR -1/1
and choose the direction you want, i.e. if you want homing to the negative X direction, leave the line as
#define X_HOME_DIR -1

No, that was my commentary. The code should look like the following:

#define INVERT_X_DIR false

#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

If the X dir goes in the wrong direction, change "false" to "true" in the first line
If you want the homing directions to be in opposite directions, you change the "-1" to "1" in the remaining lines.

WHat type of printer is it?

If a motor is running the wrong direction, switch off power and then reverse the motor plug on the controller.