WebPlus Starter Edition: Cant Edit master page

Hi, a starter novice, but I cant edit the Master page.
I followed the instructions to edit from a page within the website, and "Edit on master page". However I can only select the total master page, not the individual objects.

It feels I have inadvertently "locked" the master page, but cant figure out what I have done. I previously modified the master page, and deleted some objects.

Thanks for any help