docs: Improve selection of builder

README.md

@@ -194,7 +194,9 @@ A command line example is provided in [slsa-framework/slsa-verifier#example](htt
 
 ## Build Your Own Builder
 
-Use the [BYOB framework](BYOB.md) to create your own SLSA3 builder on GitHub. If you have an existing GitHub Action, you can use the BYOB framework to wrap it into a SLSA3 builder. This will harden the build process to meet Build Level 3 expectations and produce Build Level 3 provenance.  To verify the provenance, your users can use the [slsa-verifier](#verification-of-provenance).
+Use the [BYOB framework](BYOB.md) to create your own SLSA3 builder on GitHub. If you have an existing GitHub Action, you can use the BYOB framework to wrap it into a SLSA3 builder.
+This will harden the build process by runing the Action in an isolated environment. Generated artifacts will meet Build Level 3 expectations and produce Build Level 3 provenance.
+To verify the provenance, your users can use the [slsa-verifier](#verification-of-provenance).
 
 ## Project Roadmap