Good question person I've never met that always asks me questions which require me to make a tutorial! It's pretty simple, but knowing me I'll over explain the entire process and put pretty pictures everywhere just to make sure we're all on the same page.

How do I start?
First you need to actually login to the server. It's as simple as typing a single command. "/discord link". You'll receive a message containing your activation code (DO NOT SHARE THIS) and instructions on how to use it. Luckily you guys don't need those because you got good old Feeling!
What do I do with the code?
Open discord, find the "MCSync" bot (it will always be at the top of the discord categorized with the bots), and send him a message with the code. That's it! Now you can enjoy the bonuses that come with it!