You can do it a few ways.
I usually crumble them up and mix with warm milk. They mix up like oatmeal, kind of. They are great cos they soak up a lot of milk, so if your lo likes them, they turn out to be very nutritious in many regards.
Some people toast them and put butter and jam on them. I have never tried this persoanlly.
For me, I leave the bars whole and pour cold milk over them.
Let us know what your lo thinks of them!