I just don't understand

Andrea
My husband is building a playset with swings for our son. I am helping and I just don't understand exactly how he is attaching the swing beam to the top of the eagles nest part. We are not using a kit and it's his own design. I know he knows what he's doing but he's just not explaining it right. I asked him to drawl it out but he didn't just kept telling me the same thing again. Ugh I feel stupid