Open the Project Hub
Launch the editor and choose the Open tab in the Project Hub.
You can also use File -> Open Project... from the menu bar.
Select the Project Folder
Choose the project root folder itself.
Do not choose an individual scene file or script file. Lenga opens projects from the folder that contains the project settings and assets.
Let the Editor Load the Project
Once the project is selected, the editor loads the project structure, scenes, and assets into the workspace.
The Hierarchy, Assets panel, and the rest of the editor now reflect that project.
Use Recent Projects When It Helps
If you open the same projects often, use the Recent tab in the Project Hub.
That is the fastest way to jump between active projects without browsing through the filesystem every time.