Make the qaza of all those fardh fasts which you have missed from the day you attained puberty. However, for the fasts of Ramadan which you broke without any Shariah excuse intentionally, kaffarah and qadha both are wajib. However, only one kaffarah is enough for all the fasts which you broke in a single Ramadan.
كذا فى الدر والرد (3:391 ط مكتبة زكريا ديوبند)
You should make the qadha along with the kaffarah according to each Ramadan within a few years in winter. May Allah give you courage and taufiq, amen!
Allah knows Best!
Darul Uloom Deoband