Print not centered on build plate New and need some help!

I have a Prusa Mendel 3I diy kit.Build plate is 200 X 200mm. I am having a problem with the build not being centered on the build plate. I am using Cura and I have attached a photo of a 90 X 90mm test print. You can see from the picture that it is forward and to the left. Can not figure out what I need to do. Is it in the Martlin firmware or in Cura? I have Cura setup per instructions that came with the kit. Please Help, Thanks

It can be both firmware or your slicer.

firstly there is probably an outline on your bed that shows exactly where the 200x200 limit is, locate your 0,0 position

Put z down to about 1mm and home x and y

send the printer a G90, this sets the printer to absolute positioning
Then send a G1 X0 Y0, this moves the printer to location 0,0 (it may not move at all)
If its now not at 0,0 this is a hardware or firmware issue. You can either adjust the position of the endstops or update the firmware with the real location of the endstops.

In marlin you need to change
// Travel limits after homing (units are in mm)
#define X_MIN_POS 0
#define Y_MIN_POS 0
#define Z_MIN_POS 0
#define X_MAX_POS 200
#define Y_MAX_POS 200
#define Z_MAX_POS 200

eg if you X axis has a min endstop on the left and when it is at home it is 20mm to the left of X0, you need to update X_MIN_POS to -20
eg If you have a X axis with a max endstop and when its home its at 215mm from X0, you need to update X_MAX_POS to 215

Nb with Y axis, if its at the back it the min endstop and if its at the front its a max endstop.

With your slicer just check the dimensions of your bed. ie it should be 200x200

I am so new to 3d printing so forgive me for asking this question. How do I sent the G90 and the G1 X0 Y0 codes to the printer?
Thank you for your suggestion. Can't wait to try them.

Apparently there is a Term tab somewhere cura that you can directly enter commands into.
I don't use Cura so cant be more help there.

Some other information that might help narrow down the problem. When I run auto level, it goes to the 4 corners but when it starts the print it is not centered.

Cura is not really a printing software, its a slicer.
You would be better getting something like repetier host or pronterface to control the printer.

this is a snap shot of what I am dealing with. Do you have any other suggestions.

In Cura there is a machines settings page under Preferences - Printers - Machine settings. In there you will find entries for your build plate size and a tick box for 'Machine Center is Zero' Are the entries correct and the box ticked?