Antora it is easy:
Muslim are divided into two groups:
(1) Sunni: They are original the Ahlus Sunnah Wal Jamayaat. All Khulafaye Rashedin, Sahabi, Tabeyi, and Tabe-tabeins are of this group.
(2) Shia: This group came into exsistence after the death of our holy prophet.
Sunnis are divided into four schools or creed: Hanafi, Shafei, Hambli, and Maleki.
One of the current makkah imams,
Al Shuraim is a specialist about the schools of Islam.