Whenever you build a new bundle or perform a Sync within Servd the bulk of the work is performed by the Servd Task Runner.
Normally you won't need to worry about what it's getting up to, but sometimes tasks will fail which you need to be aware of so that you can make any required changes and retry the task.
You can see the state of your project's tasks in the Task Bar at the bottom of any project page within the Servd Dashboard. Here you can see which tasks are waiting, working, complete or failed.
Complete and failed tasks will have a link to view the logs for the task. These should be your first stop when trying to figure out why a bundle failed to build. Often it will simply be a composer or npm error which needs correcting in your project's git repo before trying again.