I don't get it.
What was this?
Huh?
I can't understand.
I don't know.
I’m a bit confused.
I’m afraid that it’s as clear as mud to me.
It’s all english to me,I’m afraid.
I’m sorry.I can’t make head or tail of what it's saying
Unfortunately,I can’t clearly make sense of what it's about.
I’m afraid I’m unclear about what it means.