CS3 is a PowerPC/Intel "Universal" binary. It will not run on any modern macOS (anything past 10.6 Snow Leopard) because Apple dropped support for 32-bit apps and the Rosetta translation layer years ago. Modern Alternatives to InDesign CS3

If you're looking for a more recent version of InDesign or a free alternative, consider:

If you own the original installation DVDs, you can attempt an installation. However, you will likely encounter activation errors.