Step 1: Open Bridgit and select the project you will be working on
Step 2: Select the task that you want to comment on
Step 3: Scroll down to the communication box at the bottom of the task and click on "Add A Comment."
Note: Here, you will also be able to view any comments previously left and add new ones
Step 4: Type your message and click 'Send' or hit 'Enter' to submit the message. Once you submit the message your Project Manager will be notified directly.
Learn more about modifying/editing comments on a task here.