dotnet console execution plan

I create a two .NET consoleApp(App-1 and App-2) and deployed on the same server.
App-1 go half way and call another cosole App(App-2) that is deployed on the same server, once App-2 is run completely then the App-1 should execute the remaining job.

What I did was...
I kept Thread.Sleep(30000) in App 1 before calling App-2, so it stoped for a while and It worked fine as expected.

Now, App-2 is taking upPredictable time limit and sometimes go to exception

What I want is..
I to want to Execute App-1 then call App-2, wait till it is completely executed then execute remaining App-1, if thier is an exception in App-2 then catch it in App-1.