Other Component call after complet method of first component

Hello 

 

We have Added two component in app.html 

 

1) For Header Part 

2) For Menu Part 

3) Router Component 

 

I am authenticate user at time of header component call but when we use authentication with .subscible .. method is call but before completion of this method .. Menu component is called .. 

 

If i want to call menu component after completed method of authentication in header component..

 

how to handle it let me know.