So if the Samples printed ok, then the printer is ok. I think there is a newer version of Cura than what comes on the USB. I would download that and set it up for the Mini and reprint at least one of the samples.
You need to take your STL file into Cura and let it process it with the defaults for whatever filament your using. It will do the slicing and prepare the gcode which you really don’t need to mess with for now. The created code has the wiping and leveling routine already in the script. I use the machine control to preheat the extruder hot end and get my filament started and feeding correctly then use the print button and the machine should cool down the hotend, wipe on the pad and do the self leveling. I always keep a spare Scotchbrite pad around to wipe the nozzle off when needed.
After it does the self level it will go to Home and wait for the bed and hotend to heat to the set points in the gcode.
FYI Not all STL files are printable, just because they load and process in Cura does not mean they will print correctly!
With Simplify 3D it will not prepare a faulty file, and if it does it will show up in the Preview mode and you can see the defects.
IF your importing gcode into Cura already processed, It might not have the wipe and leveling code.
The most important thing when troubleshooting a problem is only make one change at a time and keep it simple.