Delete

To delete something, right-click on it and select Delete from the menu.

Rename

To rename something:

1. Long-press on it and release
2. Enter the new name
3. Press the Return key on your keyboard

Resize

To resize something:

1. Select it in the Navigator
2. Go to the Properties section in the Inspector
3. Edit the Size property

You can also adjust objects in the Viewport directly by toggling between the Manipulator buttons in the Toolbar and moving the axis.

Yes. You can change an object's properties so that, for example, it appears while the user is capturing the effect but does not appear in the final video or photo. To do this:

1. Select the object in the Scene tab.
2. Go to the Inspector panel.
3. If you want the object to be visible while the user is capturing the effect, check the box next to Preview.
4. If you want the object to be visible in the final video or photo, check the box next to Capture.

Both boxes can be checked at the same time.