After you complete the West Luterra portion of Lost Ark, two slots on your character profile's gear tab unlock beneath the weapon slot. Each of these can have an engraving equipped in them. You'll find both equippable class engravings and battle (or "combat") engravings in their submenu, which you bring up by pressing alt-I. At first you won't have anything to equip, because you need to learn them by reading recipe books.

The relevant tutorial quest will give you some, and you score heaps of the green satchels that contain engraving recipes as rewards for sidequests in East Luterra, and a few after that in Tortoyk, Annika, and Arthetine. Engraving Recipe Pouches give random recipes, while Engraving Recipe Selection Pouches let you choose what they contain and are best saved for when you've decided on your build. There are separate pouches for class and battle recipes, too. (Sometimes the latter will be called 'combat' recipes, but they're the same as battle recipes.)

Right-click on the books you get from pouches to learn the recipes they contain. If you've got a stack of them, alt-clicking will let you use more than one at a time, as with any other stack of consumables.

Recipes have a rarity, designated by their color and the color of the pouch containing them. The rarities are:

Green/common

Blue/uncommon

Purple/epic

Orange/legendary

After learning 20 common recipes, you'll get three activation points in that engraving, and after that you'll have to move up to recipes of the next rarity level. Every 20 recipes at each higher rarity gives another three activation points, which means after your final 20 orange legendary recipes you'll have 12 activation points in that engraving.

That doesn't mean you'll automatically have that many nodes lit up in the relevant engraving. You have to equip that engraving first, and you've only got two slots for equipping them. What you may not realize is that you can double-stack them, equipping the same engraving twice for double the effect—something I didn't figure out for a good long while.

If you need Buy Lost Ark Gold, please visit MMOexp and your knowledge of engravings is roster-wide, by the way. Any other characters you make on the same server will have access to the same engravings as your main once they hit level 50. If they're a different class they'll only be able to equip the battle engravings rather than the class engravings, however.