How to change from the transparent mode to the following rendered/smooth mode?
Click one of the little circles in the top right of the 3D viewport - these are the preview modes (Left to right: Wireframe, Solid, Material, Rendered)
You want solid, I think.
You can also press Z in the 3D viewport and pick "solid" from the pie menu that appears.
For more info read the manual page (yes, there is a manual and has lots of useful information).