Hey there! Welcome to the TR community! 
@mcneese.chad nailed it – TrainNow takes a look at your most recent training history and recommends Productive workouts based on that. As Chad said, we have thousands of workouts to begin with, so there will probably be multiple workouts that would be a good fit for an athlete at a given point in their training. Because of this, TrainNow workouts that get loaded on different devices may not be the same. Refreshing your TrainNow page will similarly shuffle the workout options you are presented with.
@sharkin73 has a good tip for when you find a workout you’d like to do! If you happen to be “browsing” TrainNow on one device and you see a workout that looks appealing, you can click on it and schedule it on your TR Calendar so you won’t “lose” it later on.
You can also choose the type of workout you’d like to do for the day and use Workout Alternates to choose something different that will still be Productive and hit the training zone(s) you’re looking to target if the TrainNow option doesn’t quite tickle your fancy.
Here is our TR Support article on TrainNow if you’d like some additional tips:
Hope that clears things up – feel free to let me know if you have any other questions!