After making a new document, there are many features that will be available for your use. Don't worry, we will only go through the tools that you need for the first few tutorials. Make sure you follow along and remember most of them as we are going to be using them a LOT.
The Toolbox

Your main pointer. Use this for making movements, rotations, resizing, etc.

This is the subselection pointer. If your image is within a "group" of images, then you can select within the group instead of selecting the group as a whole.

This is where your resizing, skew, and distort tool is located. If you hold down this tool, it will drop a menu with the other tools within it because they are all related. We will go into more detail with this later.

This tool allows you to crop images within the canvas.

This is the Marquee tool. This lets you select multiple pixels within an area that you highlight with this tool.

This is the lasso tool. Just like the marquee tool, but it allows you to move freely rather than restricting to a box.

This is the magic wand. Used in the same way as the Marquee and lets you select pixels. Go on ahead. Use it. It's pretty magical. (If you click it in an area, it will highlight the same color pixels within the area until it is blocked off by other pixels.

All other tools are self explanatory.
Layers
If you don't know what a layer is, let me try to explain this. If you put an image on top of another image, it is two layers. This window allows you to manage between those two images. If you put one image on top of another, it will show a that the specific image is above the other.

Most of these are self-explanatory.
The only one we will use later on is the "Flatten Selection" option. Which allows us to merge images together into one.
States or Frames


These are your frames. Each frame will have an image that will follow in sequence to the previous image. When you bring down the menu, the "duplicate frame" will be the number 1 option we will use. I will go into more detail over the options at the bottom later.
If you look at the "7" that is on the right of the State's name, that is the frame's delay. To better understand that, it is 7/100 of a second. Meaning, it takes 7/100 of delay before it goes to the next frame. For now, you should keep it at 7 as it is the standard and default delay for your animations.
Menu Tools

This is where you make new documents and save your documents as well as exporting your GIF animation.

You can edit most of the stuff within the program through this drop menu. We will go into the preferences in a bit to do some hotkeys.

You can change how the layout looks through here. The rulers tool is very handy. I advise using it.

You can modify images on the canvas through here.