Step 2: Get in the mix...
Drop the egg yolk in your mixing bowl.
Put a squirt of mustard in there.
Squeeze a bit of lemon juice in there also.
You can add some salt and pepper too.
Add a bit of oil.
Start to whisk together. The mix should start clouding up and you should see it get a bit thicker or lumpier. This is the start of the emulsification process.
Add more oil as you whisk. Get it to a consistency of a runny mayo.