Well... looks like a DUMB question but, I don't know how to feed my monsters?? How can I do that?

In this game, the only time you're allowed to feed the Monster an item you purchase is when they specifically ask for it. At least, that's been my understanding of the situation. This was meant to put more focus on the Adventures rather than the Ranching itself. The real question is how it affects the Monster if you give in or deny it at that point.

Incidently, You have to go into the tent (where the monsters are training) and talk to anyone who has a (!) over their head... If you don't go in there, no one will ever ask you for anything, I found this out accidently I was in the warp world when I gave my first Item to someone... guess I should have checked in on them more.

Yah... it's like Eagle said... this MR is focused in the adventure mode, not in the ranching itself...

You should also be aware that your own monster won't get a ! but will still, from time to time, desire an item. You'll have a conversation with yourself about what item you should go get. This applies to Larox, but also to the usual "go get me a Consumable Lv 2, ta" routine.

As for what the consequences are of not getting the item/checking the trainers, for Larox it's not such a big deal--the Larox only adds one bonding (aside from any hidden affects, if any, like stress/fatigue reduction--which judging from past iterations, it almost certainly has some small affect)--for other choices, it depends. There is a regular routine with Gaufre where he skips the rest phase for the training style you're using and then asks for an item (can't remember which exactly), which reduces the fatigue by 30. I'm assuming that if you don't get it for him, you'll end up with capped fatigue (and attendant chances for injury, DNA damage, etc.)

If you watch the monsters and talk to the trainers each week, you can also tell if they're not training well, even though they don't get an exclamation point to indicate it. Sometimes you'll see it as explosions on the gadget they're using, but others it's just a different solo training action. For Zans, for instance, when they're doing well, they do this kicking motion; when they're doing poorly they balance on one foot. I assume this is an indication of stress, but it could be, oh, a sign you have the wrong type of training style going.

I notice that if a monster does this, they usually continue to do it in subsequent work/rest cycles unless you take them into combat (which sometimes stops it for a while--but sometimes not), so I think it's probably stress, but again, who knows?

Anyway, there's more going on here than most people think. If you spend a while checking on the trainers each week, you'll see.