You have to remove the moon roof their is 2 plastic covers on the inside one on each side remove them. You will see the nuts holding on the moon roof remove them. Be careful there are a couple of spacers on each side (little plated) thy are used to level the moon roof so keep them in order and in the same location. Replace the seal reverse.

The seals never truly seals Honda has designed a drain channel on each corner of the moon roof base you will see what I am talking about when you remove the moon roof. Little gutters if you will. So If you are having problem after replacing the seal with water in your cab look at your gutters not the seal. The little hoses on each corner are known to clog spray them out with compressed air to unclog them.