Before I start openly talking about smoking weed I just want to add first that I don't recommend trying to smoke for the first time until after high school. And just keep in mind that depending on where you live, there are varying degrees of legal consequences for being caught with marijuana or marijuana paraphernalia on you. In some states you could get a fine or jail time and if you have any drug related anything on your record, you can't get financial aid from the government for college. When you smoke, you take a hit of the blunt, bowl, bong, joint, etc by breathing the smoke into your lungs, like you would oxygen. When you exhale, you do NOT exhale back into the bong/bowl/bubbler, etc, you just exhale into the air. You can exhale through your nose or mouth or both. You only do one hit at a time. Once you exhale, you can take another hit. Don't cough with smoke in your lungs if you can hold it in, it'll make your chest or throat hurt. Take small hits at first to avoid that. Eventually your lungs would get used to it and you won't feel the urge to cough anymore.
Don't do it