Toolbox Window
The toolbox is the GIMPs main window. It does not matter how many images you have open all at once, you will only have ONE toolbox. When you open GIMP up, you may see some windows open by default. I would recommend closing them all to avoid initial confusion so you can start with a clean slate and be introduced to one window and set of tools at one time. You can re-open the Toolbox window you can select Tools > Toolbox from the main menu or CTRL-B in Windows 10.
The menu will look like the following:
You can resize the window however you want to suit your needs. For instance, if you click and drag the sides, you can resize the toolbox to the following:
I have created the image below labeling some of the buttons. You can view each one individually by mousing over the button and an ALT tag will appear showing you what each tool is used for.
In a later tutorial, I will cover each one in more detail. Again, this tutorial is an introduction to GIMP, to begin to familiarize you with it.
-Kathy