What Are Layers?
When using the Graphic Designer, you may find yourself with several different elements on your canvas. These are called Layers. Images, Graphics, and Text are all Layers that can be manipulated individually without affecting the rest of your project. When you're working with layers, imagine them being stacked on top of your project like a deck of cards. Along with their individual editing properties, you can also change where the order of where layers sit in the stack.
What Are Groups?
When you have more than one layer selected, you have a Group. You can select any number of layers as well as mix and match layer types. Groups are especially useful for when you want to move, adjust, or resize several layers at the same time rather than each one individually.
Managing Layers & Groups
After adding a couple elements to your design, click on the Layers & Groups icon (3 stacked squares) on your bottom bar.

This panel makes it easy to quickly go between the various layers within your project. You can also click and drag layers around this panel to change layer order. Dragging a layer to the top will move it forward and dragging it to the bottom will move it backward.
You can select a group of layers using the Layers tab or you can select each layer individually on your canvas (CONTROL + click). After you group select layers, right click on them, then select Create Group.

When your group is highlighted, you’ll notice a blue dashed box around all of the layers within the group. Using the blue circles around that box, you can click and drag to resize all of the layers within the group at once, or use the taller blue circle to rotate them at the same rate.
If you accidentally unselect part of your group, click on it again in your Groups panel and it'll highlight every layer in that group.