Get variable from other blueprint

I have a prolem setting up a variable that isn’t originally in my blueprint (its in first person character bp) and i cant call this variable on the bp in which im working. I already googled for this but as soon as i’m a reallly beginner i would gently ask if someone would be able to “graphically” explane it. The “trick” of making the variable visible doesn’t seem to work=( here what would i like to have:

Create a Get Player Character node and connect the output node to the Object node of Cast To…

https://forums.unrealengine.com/showthread.php?85862-Draw-a-variable-on-the-HUD&p=387515&viewfull=1#post387515

i love you bro tnx so much you have been really precise tnx again=)