Take them in autumn, much more chance to succeed. Just plonk them into soil no chemicals needed.
Good chance they are grafted onto a strong rootstock., they will send out
roots normally, but they will not grow as vigorous as the most vigurous grapes.
Way around this is, offer a pruning to your friend's grape and plant many not far from each other.
Planting some in pots and keeping them in more shaded conditions for a year and plant them out in the autumn the next year is what i am currently doing.
But because everybody's soiltype/climate/variety of plant/mentality of sticking to watering etc,etc is different, advice might be useless.
Best advice would be there are people who take many cuttings and try out different things, they have nice plants, the rest mostly fail. Goes for all plant propagation.
Good luck