When we started with our Nordic Permaculture we didn't have much clue about berry bushes. We simply bought what we needed from the garden shop and planted them. But that is a very expensive way, so over time I decided to get into how to offshoot bushes - to make new bushes from our existing ones. There are several possibilities for the different types of bushes.
We have a lot of different currants. We cut black and green currents as soon as we harvest them. At times I even cut them first and harvest the branch later. With that technique it is easier for me to see the branches which carry the most berries. From any good branch I cut about 40 cm off from the top and remove the leaves. That 40 cm branch I cut into 4 equal sized pieces. Each of those sticks I cut level on the top and diagonal at the bottom. The diagonally cut end goes into the soil. I place it deep down so that only one leaf eye is visible.
Some of them I plant into pots using a mixture of 1:1 our soil and potting soil, others go directly into soil on the premises. I make sure that both have enough water all the time.
For the ones in pots I have a bit more time to find a suitable place. Once they make new leaves I know they have rooted. At that point I plant them at the place I chose for them.