How do I use the GetPsimValue insert and SetRunTimeValue insert buttons in block C and what role should I play?

Hello. 

Let me ask you a question.

How do I use the insert GetPsimValue  and insert  SetRunTimeValue buttons in C block  and what role should I play?

I don't understand even if I look at tutorials or explanatory materials.

Can you tell me what these buttons are?

Thank you.