Assuming you are a premium subscriber and you have Solo mode disabled they should show up if you are scheduling them with the bots (and ghosts) and selecting the correct scheduled session.
Find the session in your Programmed (scheduled) tab in the simulator and instead of starting it, click on the Details button at the bottom.
Then look in the Riders panel at the bottom left and it should list the Riders (numbers of ghosts and bots). What does it say?
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If you click the Review button is lists the ghosts and bots setup.
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Then go back and click Setup and make sure Allow bots and Allow ghosts are both ticked.
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If all is OK click accept and then Start and all the riders should show up in 3D view.
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If not, are they listed at the top? do they show on the elevation profile.
Cheers,
Geoff