Man of Honour
What do I need to be able to repair my addons for my power armour? I had some level 15 raider stuff, but its all broken and I cant repair it. Do I need to get lucky with my perk cards and get armour crafting intelligence ones? I have some level 25 bits for the power armour but that's a few levels away yet.
You should be able to repair power armour without any perks. The most common reason for not being able to repair something is not having all the scrap needed to do so. Power armour is very heavy on resources for repairs.
When you put your power armour on a power armour frame and try to repair it, you should be told the reason why you can't. The required resources should be shown, along with how many of the resource you have. Anything you don't have enough of should be greyed out. If you do require a perk to be able to make the repair, the required perk should also be shown. It's possible that a modded power armour piece would require a perk to repair it...but if it did then you would have required the same perk to carry out the mod in the first place.
Probably a silly question, but are you trying to use an armour workstation to repair power armour? If you're not familiar with power armour in Fallout you might be trying to do that, since it is armour. Although you're never told this in game, you have to exit power armour close enough to a power armour frame, point at the frame and select the repair option. Your power armour will then be teleported onto the frame and you can repair it.
[..] I've got the hang of how perk cards work now (I think), but what controls when you get them? Is it simply 1 per level you get to pick, and a pack of random ones every 5 levels or so?
Pretty much that, but not entirely.
It's like an actual pack of cards, with the game as the dealer.
At each level, the game will select some cards from the pack and put them into a pile face-up in front of you. Most (maybe all, I'm not sure) will be added to that pile only at a specific player level (e.g. Master Hacker is one of the cards added at, IIRC, L40). These cards aren't in your hand, so you can't use them. They're just the ones that you can pick from to add to your hand. By L50, the whole pack will be in this pile.
At each level, you can choose one card from that pile and add a copy of that card to your hand.
Every 5 levels (at least up to L50), the game will pick 5 cards at random from that pile and add copies of them to your hand.
At any time, you can apply any of the cards in your hand (and only those in your hand, not those in the pile or still in the dealer's hands) to yourself, if you have enough of the required stat point available. Only then do the perks become active - they do nothing when they're just in your hand.