Japan site is from here English site is from here

Top

How to wear Yukata (for men)
1. Put the yukata on. Spread your arms out to the side, grasp the end of each sleeve, then tug outward so that there are no creases in the yuki
(combined sleeve and shoulder width). The rear seam should line up with the center of your back.
2. Pinch the collar ends together and bring them out in front of you.
(Keep the rear seam centered at the back!)
3. Making sure the yukata collar is pulled firmly against your neck (guys look cooler when there is no excess space here), bring the right panel of the yukata into your body. Hold the edge of the fabric in place with your left armpit or elbow. 4. Wrap the left panel of the yukata across your body, over the right panel.
Use your right hand to hold the yukata tightly in place at the right side of your body.
5. Hold the koshihimo (waist cord) against the front of your body, at the hip bone. 6. Wrap the koshihimo around the front of your body and cross it at the back.
7. Bring the koshihimo ends around to the front of your body and pull them tight. Tie the ends together at the side of your torso. Tuck the ends underneath so that they don't dangle out. 8. Adjust the collar of the yukata so that the base of your throat can be seen.
9. Remember: Guys look cooler with the back of the collar pressed up firmly against the neck!