Thanks Doc.
I've actually already figured out what the problem was. I didn't have the sequence activated.. ~Blushes~
After some tweaking, I've found something that works when I 'Save to Device':
To get a book that has the title 'Kim Harrison [The Hollows Book 01] Dead Witch Walking
I used
{author} [{series}{series_index:0>2s| |}] {title}
Before I figured out what the problem was, I was stuck on:
Kim Harrison [The Hollows Book 01 ] Dead Witch Walking
This was because I made a slight error in the template:
{author} [{series}{series_index:0>2s| |} ] {title}
After changing it to
{author} [{series}{series_index:0>2s| |}] {title}
It worked!
Thank you all so very much for assisting! My love for Calibre grows by the day, and I've used this program for years.