Hi! Documentation and especially tutorials is lagging a bit behind, i'm aware and trying to do something about it as often as i can find the time to.
Sadly, there's only one of me, and since the project is free, i don't have the resources available to both develop it and make videos consistently.
More videos are coming eventually, but in the meantime, i recommend:
-keeping up to date with the changelog.txt, where all the features are thoroughly introduced in a chronological order. It can take some searching if the feature is old, but it's essentially all there.
-make use of the cheat sheets and keep them close at hand: look for the Cheat sheets folder. They're also available directly on the side bar in the itch main page.
-read the other help docs (you can find them in the Documentation folder: especially hotkeys_main_editor and hotkeys_CHR_editor are important)
-join the NESdev discord and make use of the graphics-workshop and graphics-assistance channels there. There are several longtime users there who can help and i try to check by as often as i can to answer questions personally. It's become the de-facto hub for nexxt users.
-there are a few 3rd party NES development oriented tutorials that mention NEXXT and how to do specific things. I wish there was more of that, but some do exist.
And lastly, while strictly voluntary, i encourage longstanding users to join my patreon to help fund making the tool better / its documentation better. Sometimes, i also post specialized usage articles there, though the patreon posts are as much about nexxt as about my own graphical work. The patreon-associated discord is yet another space i monitor for personal user help.