I only complete entries in e.g. columns A to R, I would then like to automatically jump back to the next free cell in column A. This is in a shared sheet. Can anyone tell me how to do this as a complete novice? 

Also when I first open the sheet I would also like it to go to the first free cell in column A. 

I have tried looking through many answers and can see several questions asking the same but can't seem to get anything that actually does what I want.

I would need detailed instructions.

Thanks for any help anyone can give.