Filtrado en dropdown-leaked in dropdown

Hello, I don’t know if you could help me with a question regarding filtering and conditionals, I have a module in which a seller has to select his chain through a dropdown and based on the choice the second dropdown will display a list of exclusive branches. which I already uploaded in the app data section, I would like and appreciate it if you could give me some response, I attach photographs and I look forward to giving a more detailed explanation