These buttonholes are best on a band at least 1 1/2" wide, as they create very large openings. They will also require large buttons. Always make a test buttonhole and try it with the button you wish to use. If the buttonhole is too large, test again with fewer stitches in the buttonhole section; the technique will be the same, no matter how many stitches are used.
Knit to the row where the buttonholes will be made, drop and relatch ribbing. For each buttonhole, cut a section of contrast yarn. Bedspread weight crochet thread works well for this, since it pulls out easily after the buttonhole is completed. Manually knit 4 stitches with the contrast yarn. Repeat for each buttonhole.
Knit the rest of the band, drop and relatch the ribbing. Do Not convert any of the marked stitches; they need to remain in stockinet.
Thread a tapestry needle with a 12" length of main color yarn. Insert the needle from back to front through the center of the first stitch left of the marked buttonhole stitches. Make a backstitch, inserting the needle into the center of the first main color stitch below the marked stitches, then come back out through the first stitch just to the left.
Backstitch across the bottom of the buttonhole. Insert the needle into the 2nd stitch and come out the first, then go in the 3rd and out the 2nd, in the 4th and out the 3rd. Now go into the center of the stitch just to the right of the marked stitches, and come out under the 4th.
Turn the work around and backstitch across. Notice that this time you pass the needle under both legs of the upside down V. If you don't do this step correctly, the top half of the buttonhole will not be bound off.
Backstitch across, then pass the needle from front to back through the center of the stitch where you began in step 2. Tie the beginning and ending yarn tails together securely (a surgeon's knot works best, but a square knot will do). Work in the yarn ends on the wrong side of the band.
Repeat steps 2-5 for each buttonhole.