This is a very useful feature when using virtual instruments and buss effects (like reverb) within multiple sequences.

In the bottom right corner of the transport where the sequence name is choose New V-Rack from the pull-down menu.

This will open a V-Rack mixer window. Create your virtual instruments or aux/effect channels here.

At the top of this mix window there's a V inside an orange button. Clicking on that will take you back to your current sequence mix window. From there midi channels can be routed to virtual instruments located in the V-Rack and Aux Sends can send to busses that the effects channels in the V-Rack are using as there inputs.

When Creating a new sequence, these same instrument and effects tracks are available globally from all sequences.