Like someone said, keep it warm and let it rest. They are wobbly at first. If there was not a lot of blood, there should be no problem with that. Remember that a tiny gosling doesn't have much blood to begin with. LOL If there is no sign of infection, etc the umbilical should fall off on its own. Those long necks take a while to get under control.
When they hatch, it can take them a couple of days from piping to finish hatching. They do a lot of talking before that. If you feel that one does need help, proceed SLOWLY. only breaking a little shell at a time and watching the membrane under the shell for any sign of bleeding. If there is any, stop! Wait for a while before you try again. The blood has to drain from the vessels and the gosling needs to absorb the yoke before it comes out. If any of the shell has been removed, the membrane needs to be kept moist so it doesn't stick to the gosling. I have used a moist paper towel wrapped around the egg.
Unless there is some indication of a serious problem, it is better to let them hatch on their own. Watch the humidity, etc. Goslings hatching can be nerve wrecking. I have several eggs that should hatch this weekend. I am trying not to think about it. LOL But they are sooo cute it makes it all worthwhile.