Outlook/ Thunderbird

I had my Pop made into IMAP but that has caused problems as on one computer they did not set up on of my business emails and although that email is on the other laptop that one does not work on the other laptop

And then bringing the PST files back in as it said my laptop was full so i had to move the PST to an external drive

As my laptop was away for a few days i was using Thunderbird so i also need to know how to get the emails i worked on from Thunderbird to Outlook