I have a question about a certain topic I'm getting confused with. Basically For example - If H goes to Y, then G will go to X. Does that mean that if G goes to Y, H can't go to X?

I understand the contrastive concept is A -> B --- /B -> /A but is that all to it?

I feel as if I'm missing some major concept or lesson?

Can someone guide me to the lesson that talks about the key words, I got the for,since, because one but key words like yet, however etc. which lesson is that?