I would leave everything as it is, that's a great-looking specimen. Make a mound in the middle of the hole and drape the roots over and around it.

Perhaps i should mention what kind of rose it is. Called Gavnö.

Newly planted roses should alway be cut back so the disturbed roots when planted, have a better strength to force the new growth out. Cut the canes back to 8 inches and remove the much thinner cane to the base. Just snip a couple of inches off all the roots to further activate them into growth. Now you will have a well balanced rose plant. Place a handful of bonemeal in the bottom of the hole because bonemeal takes nearly a year to break down. Places it on top of the soil just wastes it.

This pic is a bit old well from last friday. I planted it 2 days ago. I agree about the thinner cane, i´ll cut it today, also will prune the top of the other canes, at least down to a nice bud.

There´s old soil from the nursery on the canes, do i have to wash them first? Is there any risk of a rose getting infection from the dirt? lol Cause when i´ll prune them it will have fresh wounds.

If you got it from a well known nursery, I wouldn't worry about the soil. Simple washing with water wouldn't kill anything nasty.