The first thing to do is to change the layer settings for both the Lorem Ipsum and Ipsum layers. Set "Allow seeking" to Yes.
Open the Player properties and then select Menu. From the Menu tab, select the gear icon (Additional options). From there set the navigation settings to Restricted.
You may also want to change the timing of the Down arrow on the timeline to appear after the required time to remain on the base layer, and the other 2 layers.
I also created a button mask (transparent shape) to cover the right-hand button icons to prevent the learner from bypassing the time limit on each layer. I left the outline visible so that you can find it easily. Just remove the outline before publishing. See attached.