As this is a bare root plant, soak the roots for at least 2 hours before planting, after they arrive. Plant as soon as you can. If the ground is frozen, place into a temporary pot that's filled with decent compost- once conditions have improved, move the currant plant to the ground.
Keep the plant well-watered during dry weather.̴Ì?
In terms of pruning, your blackcurrant bush will produce the best fruits on the previous year‰ۡó»s stems/branches. Make sure you trim back all shoots to about 2/3 buds of soil after you have planted. After 3 years, cut any weak/damaged shoots away, and about 1/3 of the old branches away. Apply a good fertiliser each spring to boost growth and development.