Send your clients their corresponding link and they will see the same device menus, only without the stream output menu (it’s all one audio source to them). Clients and talent can always join your conference, even if "No Active Session" yet exists.
NOTE: It is good practice to invite your clients to set their microphone preference away from anything wireless. Things like AirPods can sound fine but only when they are not also used as the mic (because Bluetooth is inherently bandwidth limited). Since most people will join on their laptops, the internal mic is a good option.
Clients sync to your Pro Tools timeline as soon as their page is loaded. While this is in progress you will see a small spinner on the top left corner of their conference tile:
Timeline Sync is designed to be fast, but for any short stretch of time it's still in progress, Postlink will automatically stream video to clients that need it. Once syncing is complete, playback draws from the high quality cache and the spinner will be replaced by a green dot: