In a bowl whisk the eggs, sugar and vanilla-whisk the hot milk in. That is custard.
You can use more bowls and double boilers but in my kitchen I'll be cleaning up so I cut to the chase. Keep it simple.
French bread is what I like to use. I cut it into squares put it into an ovenware dish and cover with the custard.
The bread likes to float so I put another dish on top to keep the bread covered.
I prefer to have more custard than bread.
Some people like it drier and add a sauce.
All custard likes to be cooked in a water bath, I would recommend it but you dont have to, just keep the heat down.