Bison Risk Management Associates is a group that teaches emergency preparedness as well as personal safety for both businesses and individuals in Northern California. Their You Tube video, although a bit long, is the best tutorial I've found on using the mylar bags and oxygen absorbers.
In the video, a round stick is used, but a flat piece of wood would be a bit easier since it wouldn't roll away from you. Another video showed someone using a left over piece of Corian countertop, while a third video used a piece of metal (actually a construction level). So use what you have around the house.
Additional thoughts:
• You can stick cooking instructions inside the bag before you seal it if you think you might need it later.
• Label the outside of the bag and the bucket with a sharpie. Be sure to date when it was sealed.
• Be sure to check that the seal was successful sometime the next day.
• Buckets should be stored in a cool location, out of direct sunlight.
• This method is best for long term storage. Use your gamma seals on buckets without sealed bags for food that you will be getting into more often.
• Don't forget to rotate your food, even grains stored long term! Make them a part of your lifestyle.
Hope this is helpful and it encourages you that it isn't all that difficult to store food long term.