Your Praetor Suit is your first line of defense against the waves of demons desperate for your blood, so upgrading it is probably a good idea. Here’s how to upgrade it on your adventure into hell.
As you’re playing through Doom, you’ll notice a number of bodies lying around on the floor. You should take it upon yourself to go and check out all of these, as some of them have exactly what you need in order to upgrade your Praetor Suit.
The kind of bodies that you’re looking for are those clad in a suit that looks very similar to your own. When you spot one, walk over to it and hit R3 when you’re prompted to do so. Your character should then reach down and pull a card out of the front of the suit. You’ll then be informed that you’ve got a Praetor Suit Token which can then be used to upgrade your suit. Simply open up the in-game menus and go over to the Praetor Suit option at the top. Choose the upgrade you want and you’ll have successfully made your first upgrade to your Praetor Suit.