would like to apply for a residence visa for me and my family

Giorgio, it's alright, you can apply for the HK residence for yourself and your family as your accompanying person. To apply for it, you have to meet many requirements and processes, such as financial and educational backgrond, language (English) level, point-based text, etc. Only after you have gone through all those processes, you can get an Approval-in-principle letter from the immigration department. Then you need to take part in an interview organized by the department. If you pass the inverview, then you will get the residence permit. The stay duration of your wife and son depends on your granted stay duration.