Clicking either of these will bring up the invitation menu. From here, you can enter your collaborators email addresses and choose 'Editor' or 'Viewer' role for them
Your added collaborators will receive an email informing them that they've been given editing rights in your presentation. You will always remain the owner of the presentation.
At present, it is not yet possible for two people to edit a presentation at the same time. While your collaborators have permission to edit and present the same presentation, there can only be one person actively editing or presenting the presentation at any given time.
Your collaborators can view the presentation while it is being edited. When your collaborators are viewing the same presentation, their profile picture will show up in the top toolbar beside the 'Invite' button.
When there is one person editing and one person viewing the presentation, the one who is viewing will see a bar appearing at the top of the editor:
Users seeing this bar will have two options:
As long as there is no one currently editing or presenting the presentation, any collaborator can press the Present button to start presenting that presentation immediately.
As the owner, any presentation or folder that you share with a collaborator will still appear in the 'My Presentations' tab with the rest of the presentations you've created.
As an added collaborator, any presentations or folders that you've been invited to collaborate on will appear in the 'Shared with Me' tab.
From here, any added collaborator can Leave a presentation/folder that they've been invited to edit by right-clicking on them (or clicking on the 3-dot button on the right side), then choose 'Leave'