add artboard, cleanup sidebar

Artboard.md

@@ -0,0 +1,17 @@
+# Artboard
+
+The artboard contains the scene of your project.
+
+## Change Artboard Size And Pixel Density
+
+Changing the artboard size and pixel density can affect performance a lot. When working with a very dense scene, You can use pixel density to get a much faster preview of what you are working on. Then either change it back before [exporting](./Export), or change the scale during [exporting](./Export). A very coarse pixel density can affect width and height. You can also use pixel density to adjust your work for a *HiDPI/Retina* screen.
+
+<video src="../wiki/raw/media/instructions/artboard/1-change-artboard-size-and-pixel-density.mp4" height="360" controls></video>
+<br>*Video: change artboard size and pixel density*
+
+## Change Background Color
+
+The artboard color can be adjusted with a color picker or by filling in a color hex code in the textbox.
+
+<video src="../wiki/raw/media/instructions/artboard/2-change-bg-color.mp4" height="360" controls></video>
+<br>*Video: change artboard size and pixel density*

_Sidebar.md

@@ -2,18 +2,9 @@
   - [Getting Started](./GettingStarted)
   - [Projects](./Projects)
   - [Layers](./Layers)
-  - Properties
-  - Animating
+  - [Artboard](./Artboard)
   - Timeline
   - Fonts
   - Export
   - Experiments
   - Roadmap
-
-- Source Code
-
-  - variableTime
-  - ofxVariableLab
-  - ofxGPUFont
-  - ofxMsdfgen
-  - dependencies