A simple packbait?
Probably the easiest is steam rolled oats (old fashioned oatmeal) and a can of creamed corn. Put the cream corn in a bucket, add a packet of kool-aid and a little bit of water (1/5 can), or add some vanilla extract or something similar. Mix this up and slowly add oatmeal so that it gets evenly coated. You should need about 2.5 to 3 pounds of oatmeal for one can of creamed corn. After the intial mix it should be fairly wet. Seal the bucket for 20-30 minutes to allow the liquids to soak into the oatmeal. Then it is ready to go. There are others but this one is really easy to make.
Now about the maize...
This is just boiled field corn. It works great as chum and can be an effective hookbait in some places. It helps to allow the corn to soak overnight before cooking, otherwise the corn will soak up a ton of water during the cooking process. Once you get comfortable with the amount of water needed in the boiling process you can safely skip this step. You will need to boil the corn for 45 minutes to an hour depending on whether it was soaked. Allow to cool and it will be ready for chumming. You can use it for a hookbait as well, but you will need to use a hair rig since the maize is still fairly hard to hook. I usually chum with maize and then fish sweetcorn over the top. The sweetcorn can at least be put right on the hook. I also add bridseed to my maize right before I remove it from the heat.
Boiled birdseed and bread crumbs also make a good simple method mix (packbait). I usually mix mine with chicken layers mash since it is cheaper than bread crumbs. Birdseed and layers mash is my staple method mix (packbait) and it is also easy to prepare. I tend to make it a bit dry since you can easily add more water once on the bank.
This should cover the basics. I hope clears some things up.