How do you edit a free model downloaded in the free web version

Newbie questions …

I created an account. I downloaded a free model.
I can view it, but how do I open it up and edit it.
Is it free or did I misunderstand?

I searched for “unlock” commands. It lists “Unlock All” and “Unlock Selected”.
But it doesn’t say how to run those commands. I don’t see any group/ungroup
or lock/unlock functionality in the little icons on the left side of the screen.

Where is the easiest to use tutorial that explains how to edit existing 3D models?

Thank you.

What do you mean you “downloaded a free model”? From where? Do you mean you downloaded a model from the 3D Warehouse into SketchUp Free? If so, it should not be locked. You will have to open the component for editing and depending on what you downloaded, there my be components and/or groups inside that larger component. To do any editing you will probably need to open components or groups until you get to edges and faces that can be edited. You can open groups and components for editing by double clicking on them with the Select tool or you can right click and choose Edit Component or Edit Group as appropriate.