You don't need to get fancy rolling tamales. As long as the tamale is tightly held inside the corn husk it will stay together while cooking and keep the tamale together. Start rolling the tamale from one edge and roll continuously into a tight little tube. Once you have the tamale rolled, fold in the point. You don't need to seal off the other end as long as you store your tamales in a tight container.
You can get as fancy as you want. One way to close off the tamale is to tie them. To tie a tamale, ripe long strands from a corn husk to use as the string. Once softened these are strong and easy to work with. While this might be more traditional, it really isn't necessary.