What are the steps to apply for dependent passes for a Vietnamese and Indian family in Thailand?

HI all. Would like to ask for your comment on my family's application for dependent passes. I am Vietnamese and holding F visa. My husband is Indian and having B visa. The kids, Indian nationality as well, are his dependents. My husband is going to quit his job in mid July and therefore to be able to stay in Thailand, 3 of them will need to convert their visas to the dependent type sponsored by me. I was advised to get a family certificate from our embassy and go to Chaeng Wattana to apply for new dependent visas for my husband and children. May I ask if this is correct or anything else we have to do to get the visas? Thank you so much in advance.