Protool can be integrated or stand-alone. When Integrated, then you can you open your Protool project in Simatic Manager. Simatic Manager just manages your PLC program blocks in any language (depending on what's installed), PLC hardware, drives, HMI's, all in one project. It is not the software where you program with, just a manager for starting up the right software. When installing Simatic, LAD/STL/FBD is installed, when you open a block written in LAD for example, then LAD/STL/FBD will start-up and open your programblock. If Protool is installed in an integrated way, then you can integrate your HMI's in you Simatic Project and you can start it from Simatic Manager.
Regards,
Combo