Hey guys,
I would also like to add one thing 
I think 3D design and 3D printing is also important in robotics field!
3D design of simple mechanic parts really is not that hard. I would suggest beginners to try it, to start creating simple parts (for example, shaft coupler, wheel hub, mounting bracket) in CAD software and then later on, they can create complete assemblies. They would have complete robot in their software, because, there are already a lot of 3D models prepared online (like motors, boards, etc). You just need to download them and insert in your assembly.
I used Inventor for years and it is pretty much fun. But I think this one is also good: https://www.robotshop.com/en/3d-cad.html
I hope there will be some tutorials soon regarding this!
Also, even better if you own a 3D printer. It is really easy to send your model part to the printer and have it completed in a few hours. I see there is one tutorial here: Intro to 3D Printing! | RobotShop Community , but I hope there will be more.