Using a condom is easy, just unravel the condom onto an erect penis right before sex and there you go. Once it’s all over and the condom has done its job, pull it out before the penis softens. It should be held against the base of the penis as soon as ejaculation has occurred to ensure it does not slip off and to prevent any sperm from escaping as the penis is withdrawn. Use it only once and then throw it away.
It’s important to check what kind of lube is suitable for use with each condom’s material as some can have adverse effects on the material. For example, oil-based lube and latex aren’t friends, and putting them together can cause the condom to break or slip off, just an FYI.