Your Instructable may include video - none, one or many - it's up to you.
(Fyi: Here's some screen cast video software: free for Windows
and free trial for Mac
Here's how to upload a video to YouTube, and embed into your Instructable:
1) Login or signup
to YouTube at the top right hand side of the site.
2) Click "Upload" next to the search bar, click the yellow "Upload Video" button, then select your video, and click "Open" to upload.
3) Ensure your video title is "How to use Google SketchUp for Ponoko 3D printing", choose the "Education" category, then click "Save changes".
4) Once your video is live, click the "Embed" button below your video, and copy the code.
5) Go to your Instructable, click the "Embed Video" icon in the edit screen, paste your YouTube embed code, then click "OK".
Next - Go to step 4 of 4 ...