I got my Milano humidor today and can someone tell me the best place to mount the humidifier? This is my first humidor. Thanks

Just throw a boveda pack in there and call it a day.

Inside the humidor will work best ...

If you have an existing humidifier, I would probably replace it ( search humidification beads etc on site). But for now, I would mount the existing device facing up not down on the cigars. If it has a Trey inside try to keep the slots partially open by careful placement of Cigars. Personally I use two smaller humidifiers one for under and on top of the Trey. I keep my cigars between 60-65℅ humidity too high remove one humidifier for a time too low refill one or both humidifiers.
Q

Also invest in a digital hydrometer ASAP.
Q
PS Please look up (Search on this site) advice on how to initialize or cure the humidor which should be done first.

Note clarification... I prefer my humidors to be right around 65.. I just monitor them and use 60℅ as my absolute min. though I will refill at any point below 65. Some may disagree and have different opinions on the matter, but this works well for my current needs. At 70℅ I find my cigars become too moist One might consider this the absolute max.but not a number that should be held for long .
Q

Hey now. He could always build and exterior case and pipe in the moisture. Kinda like the tobacconist version of shooting a wad every now and then.

What size is it? If it is one of their larger ones I'd look into beads and a couple of small computers fans. If it is a small desktop one then just some beads or a Boveda pack(s) will be fine. I suggest the 60 or 65% beads/packs. Look into a digital hygrometer that can be calibrated. 🌫

I've been using 65rh beads for years ... I was, in fact, the first in these forums to do so and did a great deal of missionary work to popularize them ... they work, and they work so well that I have no need for a hygrometer ... I used to have one that I moved from one humi to another, but lost track of it ... it's in one or another of the humis or the tupperdors ... no doubt the battery is dead by this point, but it makes no difference ... the beads work fine without my baby sitting them ...

Love it! Thanks!