This way of singing is similar to the way the church in Scotland worshipped for many hundreds of years with the Presentor led style of the 17th, 18th, and 19th century (with some still continuing this nowadays). 

The idea behind this is that if there is a psalm that you want to praise God with, you just make sure everyone has the same version of the bible (bible apps are great for this) and the leader simply starts to sing a melody slowly, and everyone follows along with whatever they are singing. If you go slow enough everyone starts to follow along easily. When we recorded this psalm no-one had heard the melody before, it was a completely spontaneous melody which we sang together.

So many of our songs are paraphrases of psalms which often emphasise certain parts which is great, but limiting. This recording and form takes the psalm translation and sings it completely, with no parts left out. 

Psalm 67 contains a chorus/refrain that appears at various points in the psalm, and I decided to loop this at the end so that we could sing other parts of the psalm over this bit giving people the opportunity to be creative and make their own melody or, just as valid, keep singing the chorus. 

When I lead this I usually stick mainly to the major pentatonic scale (common to Scottish music) and give a starting pitch so we all start well. Then I just go through it slowly emphasising which ever parts I feel God is leading me to do by making those notes higher, longer or louder. The tune mainly moving up or down the scale by step with the occasional leap.

As there are no instruments, or music, it doesn't require anyone particularly skilled in singing to lead it, it can be used in small groups, house churches, large gatherings of people, or churches where there are no instruments. 
Let's never let things like feeling we don't have skilled people, or not having the right instruments or over head projection stop us from worshipping God.