Methods likely vary depending on site/complexity. For example, are your CAD contours flat or do they have elevation values applied?
Did you have a file you wanted to share to review together? The cleanup parts of the course are the still relevant here - ie, Isolating contour linework, reducing layer count, purging, saving as clean file/wBlock.
Also, have you checked out other posts on the forum? Site Topography, contour lines and terrain setup for 3D model