Changing tires on the DB is a cinch! No need to take it to a tire shop. In most cases, the cost of changing the tire is worth more than the tire itself!
I had never changed a tubeless tire before and I managed to change the rear tire on my DB is less than 1 hour and that includes the removal and reinstallation of the wheel. The actual tire change took 20 minutes at most and I didn't require any tools (other than my air compressor to fill up the new tire!). I removed the brake disc and sprocket to make things a little easier.
Breaking the bead is straightforward and take a few seconds and a bit of grit. I used my bare hands and some body weight. I then rolled the tire off the rim. Installing the new tire was a bit more of a trick, but still easy. You basically roll the tire onto the rim. Once you get one side on, the other falls into place very easily. Patience is needed. I used some grease to lube the beads of the tire tire so it would slip onto the rim easier.
I googled how to change a tubeless tire, but everything seemed to be specific to motorcycle tires, which require a beadbreaker and tire irons. Our DB's do not require these tools and the entire process can be done by hand. Tools are only needed to remove and reinstall the wheel assembly onto the bike!
If i could descibe the process, its VERY similar to changing a bicycle tire, with the exception of you needing to break the bead, which again, isn't a big deal.