AirBNB does not support this and one of the main reason I still book via other platforms where I can do a Deposit and Final Payment.
That said you can work around it by having them book a parital stay which they pay for and then block the remaining days on your calendar. Then you need a set a reminder for yourselft to send a change reqeust for the entire stay 90 days prior to the stay.
So lets say they want to stay 1 Week then you have them book and pay for 2 days and then block the other 5. Then in 12 months you release the block and send them a change request.
Hopefully one day AirBNB will allow for mulitiple payments but for now this is what you are stuck with.
Andrew