Ok, I've got your theme working, you need to take the less folder, the theme.json and the theme.less, and put them in your root folder called nodebb-theme-nodetendo (before node_modules), delete the node_modules folder from your theme by running
sudo rm -r -f node_modules (do this in your theme folder, not in nodebb, otherwise you'll only be adding to your issues.
Your theme still won't work, as you need to actually define a few things, if you run
./nodebb dev you will see an error along the lines of
brand-primary is undefined, you will need to create a variables.less file inside your less folder and define all your CSS. To start with, just copy the contents of less from vanilla and it should run fine. (Don't quote me on that, I'm not actually a theme developer.)
Image for reference, in my case nodebb has been renamed to a different folder name.
Either way, now your theme is in the correct format, go to docs.nodebb.org and look in the guide for theming.