UPDATE FOR DRAGONFLIGHT: How does one start mythics?
Mythics no longer have looking for group, instead you have to manually create a group and find people for it. You have to be lvl 60 and there’s a recommended ilvl of 170 or so to do them (at +0, ilvl recommendations go higher higher level you go). You also have to physically go to the dungeons (they are marked on the map). You will need to learn how to use a summoning stone (you click on a party member, then click on the stone that’s next to the dungeon, and then have a second party member click on your portal to summon).
There are two dungeons per zone in Shadowlands (minus the maw). They are marked.
Press H (default hotkey) → Dungeons & Raids → Premade Groups → Dungeons
Then press Find Group.
You will find a list of people looking for mythics. You will see numbers like +2, +4 etc.
You should start with +0. You should practice in +0 for all of them before you go higher (in the future you might not have to, but for now to get the feeling). And mythic dungeons is where it’s time to read up on mechanics of dungeons and bosses. I recommend tiqqle videos and his google doc. Every video shows location of dungeon, and quickly goes through important parts of bosses and trash mobs. You can literally pull up his video right before the dungeon and quickly watch and go back.
Example: https://www.youtube.com/watch?v=3GK40hrUji8
Look for dungeons saying Mythic +0 for whatever dungeon. You can also start your own group. Don’t forget to set your dungeon to mythic (right click on your portrait, dungeon difficulty, mythic if you are making your own group).
At the end of the you will get a key for a +2. At the beginning of the mythic dungeon there is a “font of power.” That is where you put your key and with a group (that you must create) you will do the challenging version that is timed and come with affixes. Affixes add challenges and they change every week to keep the dungeon mythics fresh. But before you get to affixes, make sure you’re comfortable with +0s first.
I recommend: As you do those +0 mythics, learn what you can do in each situation. Mythic 0s are not that challenging, and many players have outgeared the content, so you can practice comfortably. Take this moment to master your class and learn to use every ability. If you are under performing don’t be discouraged. Take that time to learn what you can do improve. Once you feel comfortable with mechanics and your class, you’ll be able to climb mythic+ (meaning mythics higher than 0) easily