Assume that your trustedqsl is ready, first you need to open your application
Click on file and sign existing adif or cabrillo file, choose your desired callsign and select your ADIF file
Follow the next instructions, you may want to input your certificate password when asked. After that, you can save your signed log anywhere your like.
Your signed log now ready to be upload to LOTW website which is https://lotw.arrl.org/cgi-bin/lotw_page_auth/default
Hint: tq5 is certificate to be send to the issuer, tq6 is the issuer signed cert and tq8 is the tqsl signed log file.