In the Warehouse, you can check how many blueprints you have in stock. Level 1 blueprints are for Tier 1 and 2 ships, Level 2 blueprints for Tier 3 and 4 and so on. There are 5 Levels of Blueprints, indicated by the star symbols. The upgrade screen can be found in the armory. In World of Warships Blitz, you can upgrade the characteristics of your ship with Blueprints.
