I need some help

Others may be able to help you better, but

as Croatia is part of the EU, Croatians have the right to move to other EU states.

https://www.nyidanmark.dk/en-us/frontpage.htm

Your job situation will depend on your education and skills. Try to make a search in English on the Danish google search engine. If your profession is a very sought after profession, the language won't matter so much, but for most others only odd jobs will be available. and you have to learn Danish to find a proper job, but you will be offered free language courses as soon as you have got your CPR number.

I take that you move in at your girlfriend's. This will be sufficient for a CPR number. Living together with another person will also decrease the requirements for the income. A paper delivery job may be enough to meet the income requirements, and those jobs are easy to find.

/Nellie

Hi Nellie.

Thank you for your answer!
I have been thinking about how do I search for the CPR number? And who should I tell that I moved to Denmark?