This song, if my memory serves me correctly, moves on a 1-4-5 progression, like a preacher would when preaching, or like a congregation song, so I just freestyle on it, making sure that I usually float around those notes in the 1-4-5.
It's a fairly simple song. You don't have to pain over it.
1-4-5
If the song is in Db, then you'll just do something like:
Db\FAbDb
Gb\EAbBbDb
G\EGGbDb
Ab\FAbDb
Ab\GbBbDb
Db\FAbDb
Ab\GbBbDb
Db\FAbDb
That's the most basic way the song moves, the body of the song. Everything else is just filler. Learn it this way first, then move on to something more complex.
If you can already play this song, then it's better to post what you have, so someone can help you with the chords that you know. It's a lot easier to learn 2-3 new chords than a whole song.
Hope this helps