As long as you can still see lots of veins it should be ok. If they start to disappear then that's not good. Sometimes there just is a really fat vein.
I would get a hygrometer to monitor the temperature and humidity and incubate it in the same way you would a chicken egg, though it may need a higher humidity for the first stage as their shells are thinner. Keep an eye on the air cell - if it's tracking too big, increase the humidity and vice versa. You will need to place it in a box to help retain the heat and humidity, but ensure there are a couple of ventilation holes. A plastic box is probably better for keeping the moisture in.