Developer Guide to setup the web part for your own customization locally from debugging the web part to publishing it.
To setup download/clone the repo and run the following commands at root
npm install npm install -g yo gulp npm install -g @microsoft/generator-sharepoint
Additional info for environment setup is available at link.
gulp clean gulp bundle
This will launch the workbench where you can debug you web part.
Bundle and Package
gulp bundle --ship gulp package-solution --ship
Files to deploy will be available at path
temp\deploy and the package(*.sppkg) will be available at
Make sure to update the
config\write-manifests.json before deployment to the location where you have deployed your assets.
Additional info for deployment is available at link.
SPFx Documentation: link