First things first, here's nice basics : there is 3 types of ressources aviable in the game : you'll have to capture them simply putting a squad at them by right clicking it, or fight to aquire em.
That, is a requisition point, it provide requisition bonus as soon as you capture it. Requisition is used to build the most basic units like heretics or scout, it's the first of the three ressource you'll have to gather in the game. The longer you hold them the better as they'll get a bonus of requisition generation over time.
The last ressource is the red bar you can see at the bottom right corner of the game screen, Appart from the ork, you'll have to fight and kill models in order to build up red. This allows you to use up Global abilities.
This is the most basic information you can get about ressources there are some tip and trick you must know, ill post it in a later tutorial.