how Make an appointment at the Genius Bar of an Apple store ?

Have you tried calling the store?

.....or checked on the Apple website under Visit a Retail Store?

To answer the question directly, jump to apple.com/retail and click the blue "make a reservation" link.

In the meantime, try the following;

#1 Turn the phone off, and then on again

#2 Settings>General>Reset>Reset Network Settings

#3 Back up the device with itunes or icloud and try a full restore.

Note: Back up regardless before visiting the bar.