AFAIK qliksense app to another app navigation not available by default. u can try to search QLik branch portal.
FYI, below extension used to sheet navigation with in the app.
Qliksense desktop/sever both have default method to navigation via hub (let's u r in appA sheet1 from here u can click on hub link and it list all the available app. (i.e: the hub is your starting point and it is where you find all your apps)
There is one way u can do it,
1) u need to add that sheet navigation extension
2) once added then open "Dev Hub" from your qliksense desktop then u can look for "Single Configurtor menu" then click on it then try select app which u want to navigate from parent app.
3) find the Sheet ID /URL of app and u can call this sheet from parent app and just call via sheet navigation extension
call other app2 sheets navigation from app1:
after added, simply press the App 2 , it navigate into App2 url.
below is screen is way to get the sheet ID or URL or Ifram details of the app.