You may see a person signing calendar while using the first letter of the month incorporated in the sign. This can get confusing because three months start with the letter "J," two start with the letter "M," and two start with the letter "A." This method isn't uncommon, but it's not formal signing either. Until you get your feet under you, fingerspell the months of the year.
Here are a couple of examples:
J-A-N 22, 2022
Here you fingerspell each letter of the month, sign 22, and then sign 2, 0, and 22.
When two numbers are the same, point your palm downward facing the ground and then sign the number from one side to the other.
N-O-V 17, 2022Again, fingerspell the month, sign 17, then sign 2, 0, and 22.
The months that you can abbreviate are Jan., Feb., Aug., Sept., Oct., Nov., and Dec.
The months that you should completely spell out are March, April, May, June, and July.