I see guide to deploy on heroku https://docs.nodebb.org/installing/cloud/heroku. But mLab’s Heroku Add-on was shutdown on November 10, 2020. So I tried to deploy it on heroku but I can not. Can give me guide to deploy it on heroku by free plan ? Thanks for reading. Please advise.

You need to modify the template in the theme folder not in the build folder, the build folder gets overwritten after every ./nodebb build

@julian Yup I know. But I want to code new to understand how to do it

These should help you get started. https://docs.nodebb.org/development/plugins/ https://github.com/NodeBB/nodebb-plugin-quickstart