Answer:
Different experiences depending on which Branch of Armed Services you join, but Marine Corps Basic Training is the longest and most grueling. 13 weeks long compared to 6 weeks for Army.
They intentionally have your bus arrive at night so you are disoriented. The Drill Instructor rushes you off the bus and has you fall in ranks by standing on yellow footprints on the ground. After you file through the doors, you stand in line. When it's your turn, you stand in front of a phone where a prepared statement is taped to the wall. Something like this, "This is recruit ________. I have arrived safely at MCRD San Diego/Paris Island. Please do not send me any bulky items. I will contact you again in ____." Then you hang up. Next you stand in line for your mandatory haircut. BUZZ and you have no hair. Word of warning, everyone does it but the Drill Instructors HATE when you keep touching/rubbing your head because you may not be used to being bald. You don't get worked out hardcore or anything like that for about the first week, its mostly just paperwork but they do try and get you to instinctively respond to orders or morally degrade you to build you up. It will be hard, but that's the whole point. Good luck.