First, I can tell you how not to do it! I brought back 2 last year from Louisiana and put one in water for 2 months and then filled the bucket with dirt and left outside for the rest of the year. This didn't turn out at all. The bones are just too small and fragile. The guy I went fishing with told me this, but I had to try since I had 2 heads.
I will be doing the second head here pretty soon. He told me to buy some formaldehyde on Amazon and mix with water one to one ratio and soak head for 3 months. Take out head and let dry in the position you want it for display. He did a 12 foot gator head for me this way and it came out nice. The head does not smell at all and looks/smells better than the alligator skull I have euro mounted.
Hope this helps