As you drag watch for this diagonal magenta guide. For instance, to resize this shape you just drew, move the pointer over one of the corners of the rectangle and when the pointer changes click and drag to reshape it making it about the size of the dotted line behind it. Now most of the shapes you draw are called live shapes which means you can resize and move them without switching tools. Release the mouse button to create a rectangle. This shows the size of the shape you are creating. As you draw with the Shape tool with those Smart Guides on you'll see a small gray label appear that gives you measurements like width and height. Now starting on the dash line here press and drag to create a rectangle.
If you don't see them, choose View, Smart Guides to turn them on. These are Smart Guides and they help you align content. As you move it you might see these magenta lines. In the Tools panel on the left click to select the Rectangle tool, bring the pointer out into the document window and move it around. Now you'll draw your first shape, a rectangle. If you don't see a bounding box choose View, Show Bounding Box, if you see a Hide Bounding Box in the View menu you're all set. This is important for editing shapes and it should be on by default. Now you should see a box around the triangle.
You'll learn how to draw a few types of simple shapes like this triangle and then by the end you'll be able to add shapes to create the robot on the right. So, select the Selection tool in the Tools panel on the left and then click in this white triangle shape to select it. To follow along open this file from the practice files you downloaded and once your document is open to make sure you can see all of the artwork choose View, Fit Artboard in Window. In this section you'll learn how to draw and edit simple shapes. Creating and editing shapes is essential in Illustrator.