Spend the day - why not? You already have it off! Bring some carrots and if you have some brushes get those together. Groom your new friend and lead her around. If there's an indoor arena, take her for a walk there. If you feel comfortable enough, walk her around the property a little bit, around any riding arenas and paths. When you cut her loose in her pasture, stay there for a little bit and watch her, encourage her to come over and say hi. Have fun!!!
* I'm often reading and posting from mobile and Siri loves to make a mockery of the English language.