Just use your tongue, bruv, to cover up the holes you don't need to use. Then practise where you need to suck and where you need to blow. It won't take you long to be able to play a tune. Once that is sorted, you can try to play chords etc....that at the ripe old age of 68 I have bought myself a harmonica and I am having fun trying to make it sound like anything other than an anguished animal.
I suspect newbie bagpipe players are in the same boat.
What sort of harmonica have you got?
I'm hoping a Hohner!