Well, your question is not clear. But as far as I understand you need help to get the date. You can use Calendar() or Date(), use something like this Calendar.get(Calendar.MONTH)
to get the month and year (or simply parse to string and substring where you want).
Regarding the number at the beginning, I will assume (again, since you are not clear) that it is passed as an input. So basically you concatenate that with the “-” and the output of the previous step; the date thingy.
I hope I helped!
solved How to create a consecutive number by month