With tubeless (especially folding) it is good to seat the tire well on the bead, and make sure it stays seated.
I've found some tires work best if I install them with a tube (at max psi) and leave them like that for a few days (maybe even ride it!). That allows the tire and bead to get used to being out of the box and in the proper shape (I've had tires that I could not mount/seat tubeless until I'd done this).
Certainly, mounting the tire without sealant, pumping to high pressure, and then checking the bead seat all around both sides of the rim (does anyone do this?*) to make sure it seats properly is key to proper mounting. I find it often takes a minute or 5 to get the tire to pop onto the rim correctly (and some UST rims never do).
Its not a breaking in thing, but being conservative on that first ride is a good idea.
*When I hear of failures, I often wonder if the tire was really seated and verified.