There is no easy way for this, as Thunderbird cannot read pst files. My understanding is that it is possible if Outlook is installed on the same PC as Thunderbird. Otherwise, you may get more information by clicking the search box on this forum's website and search for "pst", as there are many posts on that subject.

See https://support.mozilla.org/en-US/questions/1394487

https://support.mozilla.org/en-US/questions/1397983

I have been able to use MailStore to send my pst file to an archive but I don't understand "copy the mbox files into the Mail/Local Folders location of the TB profile folder, with TB closed (if they aren't automatically copied by MSH)." and I don't understand what my profile is in TB to send the information to the correct TB account. I hope I am saying this correctly. I'm pretty lost with it right now, but I think I am going the right direction. Thanks for your help.

The answer is in the second topic cited above:

https://support.mozilla.org/en-US/questions/1397983#answer-1554615