Fallout – What do you need for the treasure maps

The first perk cards you 'find' are the ones in the vault when you start a new character. Those are the only ones you can find in the world and the rest are unlocked when you level up. This is either by simply leveling up and unlocking said card or by getting them from a card pack.

Each time you level up, you'll be able to pick one point to increase from your SPECIAL, and then choose a Perk Card. Each SPECIAL stat has their own associated cards, and each time you level up, new cards will be added to pick from (but not all categories get a new card every level). You also do not need to necessarily pick a card from the stat you increased. Any cards not picked will remain locked until the next time you level up, at which point you can choose another card.

S.P.E.C.I.A.L

Each SPECIAL stat can have up to 15 points. SPECIAL points are earned with each level up until level 50, and your character starts with one point in each SPECIAL. It's important to note that even though you stop gaining SPECIAL points at level 50, you can keep getting more cards every level, and there doesn't seem to be a level cap at all.

Perk card packs

Perk Card Packs can only be obtained by leveling up, and are not for purchase. You'll earn card packs at every other level starting at level 4 until you reach level 10. After that, card packs are given every 5 levels.

Sharing perks

Once you put at least three points in Charisma, you'll have the opportunity to share active perks with the rest of your team. As long as your Charisma is three times the point cost of a perk card (for example, Rank 1 of Green Thumb costs 1 point, so you could share it with 3 Charisma. Rank 2 costs 2 points, so you would need 6 Charisma, and so on) you'll be able to let your team reap the benefits of your card, and use it to plan effective strategies to synergize available perks.

Source

This looks to be the metal wall, which is learned from the "Metal Building Set" plans: https://fallout.gamepedia.com/Plan:_Metal_Building_Set

The plans appear to be occasionally for sale from either Grahm (if you're lucky enough to find him), or the faction vendor in Watoga.