How to make phpbb3 use phpmailer

[dayturnal76]

Hello,

I'm very new to phpbb3.
There is problem as not all new registered users get mails to cofirm thir registrations. I found over here advice to use phpmailer. But how to step by step do it that my phpbb3 forum uses this phpmailer.

There are links to the phpmailer.zip, some code php to use but what exactly should I change and where.

Thanks for your help in advance.