Welcome @Molato! 
Here is a getting started with magick guide. You’ll want to get your spiritual hygiene sorted out, and start work on developing your astral senses, then when you can know you have a decent chance at avoiding impostors and parasites then try the evocation guides we have on here. Enjoy and let know have any questions?
You already found the Love/Lust tutorial collection, that IS our references. I’ll be honest the get gf back has a low success rate, and people tend to get over it change their minds before it finally works and then they’re not interested, leaving the other miserable. Depending on the spell you do, love magick can cause great harm, so read a lot first and be sincere, knowing of yourself and careful with what you wish for.
I do suggest getting your protections in place first. Your lovelorn state can attract parasites that feed on your misery and seek to extend it: make sure your desires are your own and get yourself clear of influence before you start anything.