There are several ways to create a new collection in the ER diagram of a model:

- via the Actions menu:

- by pressing the shortcut Ctrl+L

- with a click of the toolbar icon

- or with a right-click anywhere in the central pane

and choose 'Add Collection'.  

You can proceed to fill collection properties and create fields.

The usual edit actions are possible on an existing collection: cut, copy, paste, duplicate, delete.

To move a collection in the ER diagram, hover the mouse to the collection title so the mouse cursor becomes a move cross:

then click and hold your left mouse button, then drag the collection where you'd like to place it.  If relationships are attached, they follow the collection and reposition themselves dynamically.

The name bar of a collection is blue.  When you select a collection by clicking on the name bar, it becomes green and the related properties pane gets displayed.  The collection window can be resized so the content fits in.

Otherwise, vertical and/or horizontal scroll bars appear:

The collection window position and size are saved with the model, so they can be retrieved next time it is consulted.

To get more information about a field, simply hover your mouse cursor over the desired field, and a box pops up with more information:

To open a new tab with the Tree view of a collection, you double-click on the collection name bar.

Most of the controls available in the Tree view are also available from the ERD view and the Object Browser.