I would put one boot on one leg and go from there. If he stands well for the first boot, put on a second one, but stop the process while you are ahead. Turn him loose, amuse yourself at his antics as he walks like a tarantula, (take a video!) and leave the boots on him for a day so that he gets used to them. You want him to be calm and behave when you take the boots off because taking them off is harder than putting them on and you need the horse to stand still. Maybe I’m alone in this but I have a problem sometimes getting the velcro undone. My mare seemed to acclimate after just a few minutes but she was older and I assumed she had surely worn bandages or leg protection in her past.
One cautionary tale from my own experience is worth noting: I bought some lovely plaid Kensington fly boots, had my big beautiful Thoroughbred mare stand still while I put one on one front leg and then the other. She was fidgeting and I had to sternly tell her to stand a few times, but basically, I was easily able to get both boots on, adjusted perfectly, and frankly, looking kind of spiffy. I stood up after putting on the second boot, took off her halter and stepped back to admire my handiwork, thinking ahead to how nice all four would look. I barely had time to indulge in my Burberry reverie when she reached down, nuzzled the fabric with her agile top lip and suddenly, seized the velcro tab and ripped the boot off her leg with a tremendous bite. Just as quickly, she demolished the second boot. I have never been quick on the draw and I think I was probably standing there with my mouth agape, too surprised to even react, much less mourn the loss of equine sartorial splendor. I was certainly too shocked to anticipate the reality of horse ownership in which I now live, wherein I am lucky to find four clean mostly functioning fly boots among my current hodgepodge collection of different brands, patterns and colors which, along with a clash of duct tape to hold the whole of it together, make my horses look like they should be standing behind saggy barbed wire and rusting car parts rather than the nice digs they’re fortunate to reside in.
Of course the boots ripped apart at the stitched edge of the tabs, completely ruining them. The velcro connected edge of the tabs stayed firmly together, however.
Brand new boots.
I’ll bet it was the next day that I read a tip on the COTH forum about duct taping the boots on horses like mine who remove bandages and leggings. Take it from me, it’s not a pretty solution but it works. Like velcro, duct tape is magic.