Build firmware from a scratch

For Developers
1

build firmware from a scratch from a new device?
is there a tutorial here

2

I created a script a while back to automate the buildroot setup on Ubuntu

3

With the OpenWRT and LEDE websites under modification, Google can be challenging right now as it comes up with broken or stale links.

https://openwrt.org/docs/start has a collection of the links that relate to building and configuring devices.