How to learn skills (crafts) from npc professions?

As title says, im leveling two professions, enchanting and engineering. Im at 400 almost but still I have level 1 recipes/crafts. I check the profession npc and it says only " you can only learn 2 profession at time" and if I check the "buy" tab, it sells me only end profession material (450). Whats the point in selling Infinite Dust and Greater Cosmic Essence if I dont have the recipe to craft anything?? I hope you get me.

And i hope im missing something because it seems weird..

Thanks for the attention.

Greetings

they're there just for the record. you get professions fully learned when you'll hit 450/450

Oh thanks for the reply! Very kind :)