Understand the purpose and use of continuous integration.

Integration is a process of integrating the code from different components of the system continuously and getting a regular feedback on each integration
In one of the projects I worked, we had multiple scrum teams working together where 1 team was working on one feature e.g. login/logout second on payments and third on billing. Then features were being implemented in the same app/ website, integration and back end services. The most important thing for the whole program was to make sure that the code from one team has not broken the code of other teams. This feedback was being received using the tests on CI server.
In second scenario, we had multiple scrum teams working on different components 1 team was working on configuration UI ,second on integration to external services ,third on integration with back end services. These components were though had a dependency on each other .In this case we were using CI server again to deploy the latest code from all teams and getting the regular feedback on the integrated code.
The whole purpose of setting up continuous integration is to mitigate a risk of bad integration and overall project failures at the later stages of the project.