The second and more Difficult I should write a guide.
for the first request, you can always learn.
I made half the engine of my alfa alone without no one helped me I don't see why not you can start from some foundation.
http://www.auto-consulting****/DWN/...dustria l e lectronics.pdf
This guide, very well done my helps you to understand how it works eeprom and flash.
I do these things to 20yo for me to do a flash player, the pc or the ecu doesn't change anything.
The guide also talks about how you process seriously on the engine, not the c....you often write.
And a bit dated but the principles are those and valid.
To me helped a lot to understand the maps.