Explain PQ Get data from folder

Hello

Can anyone explain what the meaning for the items appears when I try to get data from folder

What the uses for:
1- Parameter
2- Sample File
3- Transform File
4- Transform Sample File

And can I delete something from this list? or all items required to keep the connection

Untitled.png

I have deleted the Parameter1 and Transform sample file, and the connection is still there... any explain