You tie your horse up by putting its halter on, in the stall you click on the halter and drag it to your horses face. Now you can groom and tack it up. When you have tacked up unclip the leadrope attached and exit the stall.

J. A. Munroe has written:

'Tie-stall dairy cattle housing'

I think what you mean is mucking out your horses stall :) This should be really obvious - would you like to live and sleep in your waste? You should do this often, to maintain hygiene and keep your horse clean.

Most cattle will be turned out to pasture, milking dairy cattle will remain in the barns. Some farmers with a tie stall operation will give the cattle a couple of hours out of the day to go outside for some grass and exercise. Cattle that are in a free stall operation will remain in the barns.

stall