The addon can be accessed from the Tool tab in the Sidebar panels in the Sequence editor, node editor or 3d viewport. However it should start initially from the main scene of the sequence editor.

Select a scene strip in the sequence editor and press "Switch Scene" or Turn "Tab Hotkey Mode" and press Tab.

Scene Workspaces
when a scene is using nodes it will first switch into a scene with compositing workspace.

If your scene strip is using a sequencer input, it will first switch into its scene with a Video editing workspace.

If a scene strip doesn’t use a sequencer input and doesn’t use nodes, then it will first switch into the workspace of a 3d viewport layout.

If you change your workspace in a scene. The addon will store it the scene and always go back into the last workspace that you’ve been using.

Using the Tab Hotkey Mode
You can also use Tab Hotkey mode, and switch between the scenes using tab, similar to toggling Metastrips.
After switching to a scene, you can switch back to the main scene using the Tab hotkey only if you didn’t select an editable object in the 3D viewport, a Metastrip in the sequence editor or a group in the Node Editor, which are all using the Tab hot key as well

Scene Comp
When pressin With shift + A in the Sequence editor, you can also find add a new scene comp, which will add a new empty scene, with a setup ready for compositing.
Inside the comp scene it will have an image node by default instead of the render layers node.

More Tips
When switching back from the node editor to the sequencer scene, If your compositing was changed, press ctrl+R to refresh it in the sequence editor.
Also make sure that your Scene strip display is setup to Rendered if you want to see you comp in the sequencer.

Current Know issues:
When pressing the Caps Locks during Tab hotkey mode, the operator will not recognize the hotkey and give an error in the console. However it shouldn't affect the workflow at all