This guide is not documentation, but a condensed reminder of what you must do.
Max Makhrov has put together this very succinct guide to publishing Google Workspace Editor Add-ons to the Google Workspace Marketplace. As explained by Max the guide isn’t a step-by-step tutorial, but instead provides the key steps you should remember to do. There are some great tips in this post, particularly around what to include in the recorded screencast required by the Google oAuth verification team.
Source: 5 STEPS to Deploy Google Sheets External Editors add-on
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.