I meant editing the source of the SOLUS OS... Any documentation exists for it?
You need to modify the packages and use a local repo. I'd suggest checking out our packaging documentation.
What I am achieve is, I want to make a Linux, based on Solus. Like Ubuntu based on Debian.
You need to remove all branding, which in effect means rebuilding every package in the repository since they all ship with Solus branding, forking our branding packages, removing wallpapers, etc.. It's clearly stated on our Branding Guidelines: "The distribution of modified Solus ISOs, for commercial or non-commercial purposes, is not permitted."