At the moment, there are two ways to manage multiple projects in Swanly.
One is by using Project filter, which is available both in Roadmap view and List view. By applying the Project filter, you can bring whatever projects you need. To do that, on the top header of your Jira, click on Apps and select Swanly. When Swanly opens, look at the hand-left menu, click on the Search icon. It will load a Project filter screen like the screenshot below.
Another way is to create separate roadmaps for different projects. To do that, navigate to Swanly Roadmaps, click on the dropdown with the list of roadmaps, click create a new roadmap and include the project(s) you want.