Can someone explain stim?

Can someone explain how can I use Kat-B320 ability card “Stim Capacity”? I am lvl 10 and I have it equipped, but I don’t see anything happening. How can I use this ability?

I know that when you reach lvl 16 you get her ability “Halo” which regenerate Stim while undamaged for 8 seconds. Do I have to lvl up to 16 in order to use a lvl 7 ability? It just sound a little ridiculous to have an ability at lvl 7, but you can’t use it until you are 16.

I really appreciate your help and knowledge. Thank you!

Teammates like Marcus or CoG Gear can also provide Stim. Other than that, only Halo will do it for you.

PS: Kat is probably the worst choice to level up first, if that’s your first character. She’s the worst Horde and Escape character and has barely any use.

Thank you sir!! Really appreciate