If you want to assign the same program to multiple clients at once, it's really simple!

Simply just click the Assign Program in the top drop-down menu and then click 'Multiple Clients'. From there, just select your clients and you're all set!

Keep in mind, if you assign the EXACT same program to multiple clients, then any change will affect all of their calendars. If you want to assign the same program but keep them individual for editing purposes, then simply just duplicate the plan multiple times and then assign each duplicate to the client.