Need help making a file read only.

So I tried locking the file, it prompts me that it's locked but then allows me to overwrite it. So then I tried locking it on the read only settings, that seemed to work but then it created 2 additional files which I don't want. So then I tried using read only without locking it and it let me overwrite it again.

How can I make a file read only without extra files appearing? Or is that possible?

 

I have OS 10.3.9

I go to the get info window, I put it to read only. Then I check the box that says locked.

Then I open the file, I change it click save and it says, overwrite or don't overwrite, so I click overwrite and then it says couldn't save.

So far the files haven't appeared yet. Then I close the document, I click on don't save.

Then it creates another document with the same name but a ~ after the name. It also creates a file with a big number in this case 484-183250171-7.rft.


You might ask why am I clicking overwrite to a file I know I don't want to, but this isn't for me, it's so I can create a word template that cannot be modified for someone else that might accidently do that, sure I can save it in the locked and read only possition but I have a feeling they aren't going to like all the extra files that keep getting created.