STL challenge!!! From terrible STL to correct PART (I am ready to deal for good example and lessons)

Creator
Creator

Hi clever user, I need Yours advice Smiley Wink
I have 3D scan file (attched), that is terrible and not very nice, like in youtube video lessons Smiley Happy i use Solid Edge and I need Your best expierence, how to do fast and easy to nice body, it must be correct rectangular with bounded top, without lines ,correct planes and scale (like in attached picture) and with possibility to change dimensions, surface and etc. Most important thing, that I can to do in the future by myself a similar file. If You will attach *.part file, in which can be visible history, or youtube video link with step by step, or send me to "solidedge3@gmail.com" , I will be very thankful and ready to deal with You for reward.
Let's do this challenge Smiley Wink