You need to make a fitted waistband and put in a zipper. You can scavenge the waistband from the free Marie
pattern. If you want it to sit at your actual waist, you may want to go a size or two smaller than the size chart tells you, but always measure the pieces first just to be sure (don't forget to subtract the seam allowances!). I can't remember if the pattern calls for interfacing the waistband, but if your skirt is quite heavy, cut all the pieces again in a stiffer fabric or interfacing.
Or, instead of a curved waistband like Marie, you can make a flat waistband. Simply cut a piece of fabric that is your waist diameter plus seam allowances long, by 2 times the height you want the waistband plus seam allowances. Then, cut another exactly the same out of interfacing. You'll be folding it in half over your gathered fabric.
In either case, you'll be inserting a zipper into a seam somewhere, so leave the seam open enough to allow for that, then stuff all that gathering into the bottom of the waistband. You need to leave an inch to either side of where the zipper will go so you can fold the waistband inwards around the zipper. Once you insert the zipper into the open seam AND waistband, finish sewing the waistband.
Egads, I hope that makes sense