1. make guideline on the cover, 1,5cm between cuts, 1mm width of the cuts (according to the leather thickness you use/find). The length of the cuts is according to the leather stripe, in my case 4,5cm.
2. use exacto knife to cut all the way through the thickness of the cover. Cut on the front of the cover, not on the back this way you will have nice clean cuts..
3. insert the leather stripe through the cuts on the cover and adjusts according to the diameter of your writing tools (in my case Pentel brush pen and Faber-Castell Perfect pencil)
4. secure the leather on the inside of the cover with double sided adhesive tapes