Both these bushes are easy and hardy. You can give them anything you like in the way of manure or compost. For home made compost you can put on as much as you like. Just spread it around the root zone. For concentrated manures just sprinkle a few handfuls about on the surface and water if it doesn't rain. For what it's worth my black and red currants have been in the ground for over 20 years and have never had anything other than home made compost. They're on heavy clay with ample rainfall.

Google pruning for them. They are different species, not just different colours of the same plant, and require different pruning regimes.

Judging by the greeting I am assuming you're in Australia so your conditions may be different from mine.

I am from Canada. I can get access only to store composted manure from ship or cow.

Does it matter which one to use?

I would be cautious about applying manure compost to currants, you may get rampant growth at the expense of fruit. If the bagged compost has NPK nutrient numbers in the single digits, you should be OK.

I believe both cow and ship manure have 05-05-05 numbers

Aha - not in Australia. Sorry for the misunderstanding.

Just a few handfuls of manure is plenty. Don't overthink it. These things are tough. But be aware that these are two different species and require different pruning.