When you bring your steed to the Stables, claim a stall for your use by making a topic for your beast. If you have a picture of the creature, that would go well in the first post--or at least a description, so that others strolling through the rows may admire your mount. Whenever you bring your steed to my home, your stall will always be here waiting, so you should not create new topics for that beast. If you have more than one mount, then when you ride each one in you may claim a new stall for that particular beast.


EDIT: I see no reason why you should not place creatures you have acquired in the Art Shops of Gaia in your stalls. Be warned, however--I will not have feedable beasts starving here! You shall come and care for your creatures, not depend upon myself or any others to do so for you. If I find beasts starving and miserable here, I shall remove them from my stalls and set them free. Also, do not claim large numbers of stalls for your entire collection unless you are willing and able to come here yourself and care properly for all of them.
If you understand and accept these rules, then all should be well.