why has my bookmarks not been synchronised when I transferred my mozilla browser to a new laptop

If you still have access to the old laptop, you could sign in with both installs of Firefox, and sync your bookmarks that way. https://www.mozilla.org/en-US/account/ Or did you mean you had tried that, and it isn't working? (It sounds like you did something to transfer from the old installation to the new one, I'm not yet 100% clear what you've tried.)

The details for Sync are here: * [[Back up and transfer your Firefox data to a new device]]