wave riding in the river

One day me and my friends went to a water park in the river that is meant for kayaking/surfing. We went there just to check it out maybe even go inside the water. We saw some little kids they were probably like 13 or 14 and they had a few boogie boards and they where riding the wave like nothing. It look really fun, but we didn't have a board to ride with. One of my friends ended up stealing one of their boards. I did not approve of this and had nothing to do with it. Next day we went there again and tried riding the wave. It was harder then it looked. We spend all day trying and trying but the river just took us away. We couldnt even stay there for a second. Then we finally found out it was really simple to get into the wave. You just had to smoothly go with the river flow and lift the top up.