Where was Thanos at the beginning of endgame ?

Josh Brolin as Thanos  

Thanos has appeared in Marvel Cinematic Universe 5 times so far 

Thanos Is The Biggest Villain Ever In Marvel Cinematic Universe  

Thanos was on Planet 0259-S, also known as the Garden,

is a greenfield planet where Thanos resided following the Avengers Infinity War (2018)  

If You want to watch All Avengers movies Appeared Thanos in English language visit on Google Play, Apple iTunes.

All Avengers Movies can be also seen on Disney Plus Hotstar in English & other Multiple dubbed languages.

34 Best Thanos Dialogues, Quotes in Hindi & English 

How did Thor get fat?