There are a few ways to add content to your UE4 project; however, we'll focus on the Content Browser's Import functionality.
Now that you're inside the 'QuickStartContent' folder, click the Content Browser's Import button to open a file dialog box.
Locate and select the Basic_Asset1 and Basic_Asset2 FBX mesh files.
Click Open to begin importing the FBX mesh files to your project.
Inside the editor, the FBX Import Options dialog box appears. Clicking Import or Import All adds your meshes to the Project.
Click the Save All button to save your imported meshes.
A Save Content dialog box appears. Click Save Selected to save your imported assets.
Navigating to the 'QuickStartContent' folder, verify that UE4 created the corresponding .uasset files.
Organize your assets so that you can easily find them.