I've been planting roses since I was 14 (that's 55 years) and I have always used the method I was taught then. I dig a hole and partially fill it with John Innes No 3 compost with some FBB (Fish Blood & Bone) added. Then plant the rose with roots spread out and backfill with more John Innes No 3 to fill the hole and gently tread in to firm up, making sure any graft area is above the soil.
If Roses have been planted there before then use some Rootgrow Mycorrhizal Fungi available in GCs around the roots as you plant it, but it isn't really necessary if roses haven't been planted in that spot before.
One of the problems that can/does affect roses is black spot and I add about 2-3 litres of peat to the base of the plant and gently fork it in to help prevent this.
There are those who say we shouldn't be using peat in our gardens but the amount gardeners use is pitifully small compared to the commercial extraction which is then used as fuel to burn. At least gardeners are putting it back into the earth where it belongs.