I have a lot of books that are part of a series & am really struggling with my OCD to organise the books in the correct numerical order on my tablet.
I have tried numbering the books as part of the title, as 01,02,03 & so on also as 1,2,3 & so on, but cannot get the books to appear in the correct numerical order.
I have an Amazon Fire HD10 7th generation,using Moon+ Reader Pro & just started using calibre Companion.
Where am I going wrong?Can someone please help with this?

It may seem as a bit petty but its really getting me down.
Thanks in advance.

What you're trying to say is that the books are not correctly sorted in the library application on your tablet? Or are they sorted incorrectly in the file browser on your tablet? Because these are different things. File browser sorts using the filename only, and correct renaming should take care of that. Library app most likely sorts using book metadata, which means you need to edit book metadata to ensure correct order.

Fixed. Thank you for the help