This guide will let you how to claim rewards for Faction Missions in Warzone 2 DMZ Mode.
First, you have to boot up your game and select the faction mission at the bottom of the screen. Now when you file, it will automatically claim the reward for you. You need to select a mission from here and then fulfill that mission to get the rewards. There is no method to claim the rewards, you have to exfil and then select other missions to get the reward automatically.
Now if you go to the weapons stash, you will find weapons added to your stash by completing the missions. To get the blueprints, you need to go to the insured slots and then go to change. Choose the gun whose custom blueprint you just have saved. Then you can see your custom blueprints which will be indicated above the armory as it is shown by a ranch sign. You can build custom blueprints for almost every type of gun.