Nutrient instructions often say to dissolve in a small amount of water. Honestly, I sprinkle the nutrient on top in a very thin layer so it doesn't clump, then stir well. I use a drill-mounted stirring rod, and it works great.When adding the nutrient to the must do you mix it with water or just sprinkle it on top like you do the yeast? Does it matter if you add it before or after the yeast?
I add the first dose of nutrient before yeast. The second dose is added in a similar fashion, just before a punch down/stir of the must.
In the past I've used various methods for inoculation. Kits often say to sprinkle the yeast on top and don't stir. I've also rehydrated the yeast with warm water and a bit of sugar, letting it set for up to an hour. This work successfully, although fermentation can take up to 72 hours to kick off.
Very recently I made Finer Wine Kits, and followed their instructions (mostly). Assemble the must on Day 0, including nutrient. Make a starter with yeast, their starter nutrient, and 1 cup water in a wine bottle
On Day 1 (roughly 12-14 hours later), pour the starter slowly along the inside of the fermenter so the starter doesn't spread much. This has produced a ferment start within 6 hours (no visible activity, but I could smell it).
The kit instructions state to wait 18-24 hours before inoculating, but doing it the following morning worked out well. This has been at low temperatures (below 65 F).