I just finished my GSSL after a long time troubleshooting it, I know some times it can be exasperating, but, believe me, EVERYTHING s in the thread, every issue you're having is almost for sure covered in the thread, even if you think your problem is unique and rare, it isn't.
Someone, somewhere in some place had been where you are now and asked here, surely it will be answered by some smart guys, and with a bit of luck, it is explained many times in different ways. There's no better guide than the experiences of other people.
I readed the whole thread before start the building, but no so seriously, giving it a few more hours would saved me TONS of hours and headaches, and also some cash.
Also, googling something like "gssl build" should give you many links to blogs showing different people building it.
A guide, strictly talking, I don't know anyone, it isn't a videogame