The integration is possible only when you allow tasks to your % based project. You can connect percentage based projects in Ally to project management systems like JIRA, Asana, SmartSheet and Wrike, with many more on the way.
To see the integration options, add tasks to your % based projects:
When you use a task list in Ally or connect to these systems, progress of the project is automatically computed based on the number of tasks completed vs outstanding. You can edit a project to add an integration after creating it without one. When that happens, project progress will be recomputed based on the tasks.