How to put on a face?

Hi how do i put a face on this?

4444.skp (2.3 MB)

With the sanboxtools maybe?
(Select the contours, than create surface from contours from the sandboxtools).

I first purged your component list, reducing the file size to about 1/8. Please purge your models before uploading them.
I got the bottom to fill by redrawing edges or drawing new edges across your model. Last I erased theextraedges I had drawn.
4444b.skp (566.4 KB)

Anssi

If you’re asking about creating a surface along the top, I took @Anssi’s model and added a surface:

I relocated the model so that the outer circle is centered on the origin. 4444c.skp (392.3 KB)

Thank you so much!