If you encounter something you don't know how to do or say in Engpsh, you can say:

"I'm not sure how to do/say that."
"I'm not famipar with that."
"I'm not sure what you mean."
"Can you explain that to me?"

For example:

"I'm not sure how to use this software. Can you explain that to me?"
"I'm not famipar with that term. Could you explain it to me?"
"I'm not sure what you mean by 'XYZ'. Could you explain it to me?"

These phrases can be used to ask for clarification or help when you are unsure about something. It's always okay to ask for help or clarification when you need it!