Warm your oil and beeswax together on low heat in a small heavy bottom pot, double boiler, or a pint jar in a pot with a couple inches of water as a makeshift double boiler.
Warm until your beeswax is just about melted, then take off the heat for it to continue to melt.
If you're adding essential oils, make sure the oil/wax mixture is cool enough that you can hold your finger in. If not adding, pour your mixture into small jars for storage.
Label it! You think you'll remember...but you wont.
Let cool, and tuck away for when you need it.