I found the answer by myself just in case any other beginner searches frantically to see their classic viewport again.
Simply go to top menu >Window > viewports > the click > viewport1
In wish we’d get answers to questions and not messages “Thanks for spending time with us” etc.
When one comes from the SketchUP forum that is ultra helpful very often in minutes or just a few hours. I find it very this forum very quite.
I guess because my beginner questions aren’t very interesting.