Best practices in Gnucash file management

[Bob Alexander]

Dear friends,
after a few days using Gnucash, with your excellent advice, I start to 
feel very happy about using it (even though if I was rich enough to not 
having to use it at all I would maybe be happier :->).

I now see that the data I am working with is kept in a file called 
"sample gnucash file" and there are a bunch of .log and .xac timestamped 
files.

Questions:

1) Can I rename the "sample gnucash file" to something more meaningful ?

2) Can I delete the "log-xac" files from times to times ?

3) Other backup suggestions in case files "break/corrupt" ?

TIA,
Bob