How to register accounts manually

You register manually in the emulator inside the WhatsApp app, the same way you would on a phone (you can run several emulators at once and register them in parallel):

Enter the number → receive the SMS → enter the name, set an avatar, etc. → in the program, click "Save current account" → the account is saved to the program and the data in WhatsApp is automatically cleared → ... (repeat if needed)

For registration you can use your own numbers or take them from SMS services.