Configure new project to use build.sh not cmake or makefile?

Looking to use CLion as an IDE for some open source code I'm modifying. I'm running on a M1 mac osx 12.6.3 using CLion 2023.1.1.

I've verified a new "test" project configures and runs correctly using the "hello world" main.c example -- even with some extra mods! SO - Build,Execution,Deployment Toolchains, etc are all correct for a new clion CMAKE project.

Now I need to setup a new project for an open source codebase I'm modifying. The key issue: the open source build uses a build.sh script to compile all sources. 

How do I open the project and have CLion start from where build.sh points it to? 

I assume I do not want it to clean the project? 

Can someone point me to any documentation on how to setup a project this way? I've read all docs on setting up for shell scripts, how to edit Run->Edit Configurations and Add New Configuration for a shell script, etc. 

Is there *any* guide or tutorial to walk me through this? 

FWIW - this is a first step to just get the base code to work. Once I make changes there is a second script I will need to run, again similar to build.sh but new.build.sh.

And yes, the CLion CPP-A-179994647 indicates this code base *is* supported. Please help..... thanks.