Having one branch is the simplest strategy you can use. If you have only one developer working on the app, there is no need to create a branch. Even when there are more developers, they could still work on one branch, merging their changes into it each time they conflict. But it is hard to keep the product stable because half-done changes could be pushed into the branch:

To stabilize the app, you will need to pause development. Still, you can change the strategy to something else later, when you see the need for it.