Sudetenland was the outer region (the far north, west and south) of what is today the Czech Republic (Bohemia & Moravia province of Austria-Hungary). As they were German speaking, not Czech speaking, Hitler rather liked them and wanted to empower them in a BIG way.
Czechoslovakia had just been given indepedence after WW1, and this gave the Czechs (with capital city Prag) full power and control over the Sudenten Regions. Hitlers Plan was to create a country of Sudeten that could rule over the Czechs (who were&are Slavs, and Hitler hated Slaves).
He also wanted to return the Prag university to being German-speaking, just as it was when it was Europe-s oldest and greatest university.
His plan backfired when he lost the war (WW2), and the Sudeten were all deported, their posessions all taken away, all were left extremely poor, homeless, uprooted, and the Czechs were left in posession of ALL land and all businesses on Czech land.