Complex sentence: In the next years he managed to enter a graduate from physics and mathematics department of the Moscow State University (July 24 1931) and then get a job at the Central Aerohydrodynamic Institute (TsAGI) under Mikhail Lavrentyev and Sergei Chaplygin.
Split into simpler sentences: In the next years he managed to enter and graduate from the Physics and Mathematics department of the Moscow State University (24 July 1931). He obtained employment at the Central Aerohydrodynamic Institute (TsAGI) under Mikhail Lavrentyev and Sergei Chaplygin.