For tickets requested within a single application, those seats will, as far as possible, be located next to each other. For tickets requested via separate applications, you and your friends can increase your chances of being seated together by giving your friends your group ID number when applying for tickets.
When you complete your application, you will receive a unique group ID number. This will be indicated on the page confirming your application, as well as in the confirmation email. If you share it with your friends, they can then provide that group ID number when they submit their own ticket applications. This may allow you to be seated together, subject to the availability of seating.