Use this phrase to talk about whether you can understand someone:

Do you get what I'm saying?

There are a variety of different words with similar meaning to "say" which can be used in this way:

Do you get what I'm suggesting?

I'm not sure that I get what you're implying.

It's common to use "trying to ___" in this phrase when someone is not being successful in their communication:

I'm sorry. I just don't get what you're trying to say.