When modeling interaction between Processes, Bizagi provides smart-align options for both the new Pools and Message Flows between them.
New Pools alignment
Recall that as soon as you open the Modeler a Pool will be ready for you to start diagramming.
When including a new Pool into a diagram, using smart alignment to line up the Pools to each other (left vertically alignment).
To use this feature, Add the pool and then, drag it to the existing Pool's left start point (vertically near).
Bizagi shows a yellow dotted line to indicate the center of the existing Pool, so you may drop the new one at this location and allow auto-alignment.
Message Flows alignment
When using Message Flows to model the interaction between Processes, smart alignment will show flows emanating from a straight line parallel or vertical to the element.
To use this feature, make sure your Task or Event being connected to the Message Flow is placed close enough to allow for a straight line.
In this way, Bizagi will automatically align the Task or Event.
Note that this feature applies for Message Flows connected to Tasks or Events, and at least to one of their two endpoints (e.g Message Flows with the following related elements: Task-Task, Event-Event, Task-Event, Pool-Task, Pool-Event).