Before you start, if you don't already have the ability to make those giant square ice cubes I would strongly advise getting a silicon mold so you can. They are not just for looks: the extra area keeps drinks cooler for longer and the melt is much slower which means less dilution.
Step 1: in a glass that is short and wide with a sturdy bottom combine 1/2 oz maple syrup, a few drops of orange bitters (or 1/2 oz of orange juice squeezed from the orange you need for step 2), the juice of a quarter lemon, and a few dashes of Angostura bitters
Step 2: Add an orange wheel to what you've mixed together in the glass and muddle. If you don't have a muddler, anything with a wooden, rubber, or plastic bottom can work.
Step 3: Add 2 oz of bourbon and stir well
Step 4: Put your ice into the glass and then add as much seltzer as you want to taste and/or situation.
Step 5: Drink