This is Rose of Sharon Cassidy. The first time you talk to her, she will give you a quest. She tells you that her caravan burned down. If you want to find the quest for the caravan, go to Crimson Caravan. Find the Crimson Caravan according to the location given on the map, and find the boss inside, Alice McLafferty. She is an old lady. Talk to her and ask her for a task. She said that she only has an errand job at the moment and asks you to send a letter to a Doctor. No matter what it’s called, it’s at Camp MaCarran, the airport camp in NCR. Go find the old man named Beast, and he will give you a mission to go to Vault 22. Ignore this for now. After you deliver the letter, you will meet the old lady. When the old lady is satisfied, she will give you three more tasks. The first is to go to the Atomic Wrangler to find a rich second generation whose name I don’t remember, and then persuade that guy to voluntarily quit the caravan. The second The first is to acquire Cassidy, your future teammate's caravan, and the third is optional and is to steal information from Gun Runner. The first and third ones have nothing to do with our purpose, so go back to Cass to buy her caravan. Go back to find her and talk to her. You need at least 50 Speech or Barter to convince her, otherwise you need to bring her She has at least a dozen (12) Whiskeys. In short, after you meet the conditions, she will agree to sell her burned caravan. In fact, it is just to buy a caravan trademark. You can then talk to her and ask her to join you. Cass will give you a special skill, Whiskey Rose, which will allow you to drink alcoholic beverages without any debuff (that is, drinking will not reduce your intelligence), but this special skill is only available when she is your teammate.

That’s detailed enough