Ken, congratulations on your new purchase. That is a beautiful tree! What variety of orange is it?

Susanne gave you some good, helpful tips. I am sure others will chime in also.. I would like to add a few comments..When did you pot up your citrus? Does the soil contain a wetting ingredient?? Citrus does not do well in wet, soggy soil. They need a well draining soil. Look up the 5-1-1 soil recipe or the gritty mix recipe. If you are unable to get the ingredients, you can use a good, lightweight, well draining potting mix that does not contain a lot of peat and mix in a good amount of perlite. Repot right away so your citrus tree has a good, aerated soil that the water will drain through well and the roots will have the supply of oxygen that they need. Make sure the pot has plenty of drainage holes. Put a block under your pot to raise the pot up so it does not sit in the water that drains out. Check the soil before watering by sticking your fingers down in the soil a few inches to check for moisture. You want the top few inches to dry out between waterings. You can use a dowel to check for moisture. Citrus like to be well fed with a good npk citrus fertilizer. Since it is late in the summer you need to make sure you fertilize lightly for the last time. You do not want a lot of fresh new growth..(You can mix in a bit of Osmocote Plus slow release fertilizer )..They also like at least 6 hours of full sun a day. Check often for pests like mites. With winter approaching and your potted citrus will be inside the mites like hot dry conditions. Spray your tree with water daily to keep the leaves moist and give them a shower every few weeks.. you will not need to water the trees as often in the winter once indoors. You want to prevent root rot.. Citrus should have plenty of light in the winter to prevent leaf drop. Put it near a window thst gets plenty of light. Turn the pot on occasion so all the leaves get some light.. You can also use supplemental light for the tree.

I would not put your new citrus out in the direct sun. Put it in the shade for a week then part shade to slowly acclimate it to the sun. Otherwise you could burn the leaves. A few weeks before bringing indoors you need to acclimate your tree again.. part shade, full shade. Start a spray program against pests by using a horticultural oil, neem oil or organic soap.. you want to do this at least once a week for three weeks before bringing in. Only spray early morning or later in the evening when temperature is 80 or less as to not burn the leaves..