Professional tour guides will come to answer your questions. Thailand can apply for visas on arrival. As long as you have a good passport in the mainland, you can go directly to Hong Kong to hold a group. When you arrive in Thailand, you can apply for visa on arrival and Thailand. You don't need to endorse. You can just go and have fun. The fee is 1000 baht, 250 RMB. This does not include the tip, 30-50 RMB. You can ask Thailand directly if you have any questions. The tour guide knows best.