Hello,
1. %TRACKBACK% simply gets replaced by the complete trackback URL through which user can immediately see the submission. So when you put it inside the redirection link, it redirects to the trackback page. Some other replacements are available. Please read about them here: https://ipanelthemes.com/kb/fsqm/form-submission-related/understanding-different-redirection-types-submission/#ipt_kb_toc_635_1
2. %SUBMISSION_ID% is the numeric ID of the submission. %TRACK_ID% is the encrypted version of the same numeric id, that the user needs to enter in the trackback page so see the submission. https://ipanelthemes.com/kb/fsqm/fsqm-primary-setup/setup-trackback-page-user-portal-page/
More available format strings are written here: https://ipanelthemes.com/kb/fsqm/form-submission-related/available-format-strings-custom-notifications/
If you want to appreciate my efforts, then please rate our products. It helps us establish stronger reputation across the marketplace.