Using a new file in Onshape, try to duplicate the piece above. When you have made your piece, create a drawing file showing the top, front, right side views as well as the isometric view, and insert into your portfolio under a new page called "Onshape". Dimension your parts prior to exporting as a PDF (Portable Document File).
For more practice try to recreate some of the shapes found here. When you finish upload them to your portfolio and share them!