Problems starting

I am new to 3D printing, and although I am a retired electronics engineer, the 'architecture' of 3D printing is completely new to me. I have MK2 printer and am attempting to run the "V2calibration.gcode' program. The first problem was that the test sample wasn't sticking, although it did try to make the zig-zag pattern. I made a change to the Z axis, but now the filament just comes out bunched up with nothing sticking to the plate. I don't know how to get back to the basic setting, even though it wasn't sticking. I have cleaned the base plate. One thing I found odd was that the temperature for the nozzle (255 Deg. for ABS), changed to 210 when the V2 Cal. program started. The plate temp. also dropped to 55 Deg.
Help!

Printers run g-code [reprap.org]

Its just a text file
If you look at the start of V2calibration.gcode

It sets the temperature.

M104 S210
M140 S55
M190 S55
M109 S210

these are standard PLA temperatures


Regarding cleaning the build plate, be careful what you use, some thing leave a residue

I wash mine if good old dishwashing liquid and water
Wash and dry it
Then I wipe down with isopropyl alcohol on a plan white paper towel. Don't touch the surface of the bed with fingers, fingerprints == oil == no sticking.