All of my perk cards are level one. I have had the best ones eqipped since I got them but they are not levelling up. What are you meant to do to level up the stars on the perk cards to get the benefits that come with the higher ranks?
Perk cards in Fallout 76 do not rank up on their own or from using them. You need to obtain two of the same perk cards. If you have two level 1 cards that are the exact same, you can combine them together to make a level 2 card. Then later on you can combine another level one card with the level 2 to create a level 3. This is the only way to rank the cards up. They will almost always be level one when you obtain them and you have to combine them together to upgrade them.