If you are looking for step-by-step tutorials, then you should go to the pages of VEX Builds (V5 Build Instructions - Downloads - V5 - VEX Robotics) where you will find instructions to build various trainer examples of different designs. Once your team has become more advanced, fully understanding the VEX building system, you can then progress to figure out how to build various mechanisms on your own, perhaps by seeing an example from another team (like a “reveal” video.