Helper are small things that help you. I call them helpers because I'm not sure what else to call them. They are all found under the View menu and they'll always be there for you.
This small box let's you see your whole diagram in miniature. The blue rectangle in the box shows you the current viewable area. Drag that blue box around to zip around your diagram. Much better than scrollbars.
To show/hide Quick Navigation:
The Grid helper just shows a grid behind whatever you're doing. You can choose to snap objects to it, or just use it for a visual guide (but in that case I think it's often better to get a background image with a grid pattern exactly as you want it).
Use the grid properties dialog to control things like line color, the size of the cells, whether the grid is in front or behind your stuff, and whether to include it when you export your diagram to another format. ( View > Grid properties )
To show/hide the grid:
To enabled/disable snap to grid:
Rulers help you get a sense of position and size. They're not so powerful yet because you can't drag out guides, but we'll get to that eventually. Rules will update their units based on the units you set when you created the document: pixels, feet or meters.
To show/hide rulers:
Quick styles is the place for you to save certain stroke and fill styles you'll be using a lot while working on your diagram. It has six boxes to store six styles:
To load a style into a box, you just eyedrop a shape that has a style you'll be using a lot. Then, click an empty box in the quick styles dialog. That box will save your style. Whenever you want to use it, just click it with an empty eyedropper.
If you want to change that box later, just drop a new style on it from a full eyedropper.
To show/hide Quick Styles: