Bug fix in React native (android folder )

Hello , i need help in fixing bug in react native cli app (android folder) .

Note : work is only inside android folder created by react native so u should know android as well

Requirement is getting authentication details from external portal (which i have document where we have to follow to get authtication token )
But problem is it in andorid (step by step instruction in android )
So need to work on the android folder created by react native app .Based on the instruction in document have to code in android and achieve the functionality .