Use a microplane grater to crush/grate your garlic. If you don't have one (and you should!), you can mince it, but it'll be better incorporated into the dressing if you can really crush it.
Add the garlic to a mason jar.
Add the lemon juice, salt, and anchovy paste. Put a lid on and give it a quick shake. The anchovy incorporates better if you shake it before you add the oil.
Then, you need to coddle your egg. You don't HAVE to if you're using a pastured egg (which I am), but I've read it makes your dressing a bit smoother. So, I coddle it. Bring a pot of water to a boil on the stove, then add the egg for exactly 45 seconds. My timer is only in minutes, so I set it for 1 minute, then wait until it ticks down to 45 seconds, and quickly add the egg. When it beeps, it's done.
Add your avocado oil. Some say it emulsifies better if you slowly stream it, but I'm lazy these days and just want it done. Add the lid and shake.