It looks like HDB have launched 4,583 Build-To-Order (BTO) flats and 1,952 Sales of Balance Flats (SBF) today. You can submit online from 27 May 2022 (Friday) to 02 June 2022 (Thursday), 11.59PM. You can apply for only one flat type/category in one town under either the BTO or SBF exercise. I will only highlight certain important information based on my past experiences.
May 2022 (BTO)
May 2022 BTO