Got a new phone

Hi. I have just switched from a Samsunh A10 to a Samsung 32
I used Samsung smartwatch to transfer all apps and data. It transferred all my K9 inbox but not my sent messages or those in my trash folder, ( need both)
Could anyone please help me with this. I am not a big user of tech things so the simpler the better . Thank you in advance

Sounds like you are using POP3 to access your mail and not IMAP. I suggest switching your email access to IMAP. Then folders like “trash” and “sent” can be synchronized. Unfortunately, for the existing messages, there is no way to transfer them (other than forwarding them one by one).