Arrived in Helsinki 9 days ago and already got a ticket

I have a week to pay it and their IBAN, however i havent got a finnish ID yet as I am waiting for 26 November to have my appointment. Im here with my fiancee. Anyway, how should I pay this, as I dont have a Finnish bank account.
Can i pay it from my Croatian account, or I should go personally, dont even know where, and most important question : will this fee notice be sent on my Croatian adress as I provided them with my croatian identification? I want to avoid this in any case. Or it will be sent to the adress i gave to the Customs when I entered the country?
Thank you so much this is my first fee ever and i am panicking here..... Cheers!!!
What happens if I am late paying this fee?