Making a phone call using Uk sim on roaming abroad

[phil-k]

I am going to Copenhagan and when I arrive I have to make a phone call to collect the keys. I have been given a 12 figure number to call starting with 0045 and then 8 more numbers
I am using a 3 mobile sim with roaming enabled, will I have to also enter anything else
Thanks

 

[phil-k]

Thanks