See https://support.mozilla.org/kb/installing-addon-thunderbird

thanks Chris. ive got it now but it very complicated .am wondering if theres a simpler add one to make backups thanks

Not that I'm aware of. For creating profile backups you might also try the Export function. Tools (Alt-T) - Export

i could but there are way to many backup options...it would days to research them all

A simple way is to - exit TB - copy c:\users\<yourid>\appdta\roaming\thunderbird to an external drive. This always works, assuming you have not moved the profile yourself to another location.