one of the typical tunings is to 'here comes the bride'

just sing that to yourself and you will hear the proper interval for two-conga tuning.

I dont quite get that....

The Richard Wagner piece entitled "Bridal Chorus" from the opera Lohengrin. In the US, it's referred to as "Here Comes The Bride" which is used as a wedding march as the bride walks in.

The reference to "Here Comes The Bride" is with respect to the first few notes of the melody. The lyric "hear comes the bride" outlines the interval of a Perfect 4^th. It's the same interval used on standard tuning of a bass guitar and the lower section of strings on a six-string guitar. If you play piano you can realize the interval by playing a C, then go up to the F. The distance or interval between these notes is called a Perfect 4th.

When tuning your Congas, you can use any note reference that you want, it doesn't have to be C and F. But the distance between the notes, the interval, if you want it to be a Perfect 4^th, would sound like the beginning of the mentioned wedding march.

When tuning to a Minor 3^rd, you can use the theme song to Beverly Hills Cop, "Axel F". The first two notes are a Minor 3^rd apart.