250mg/day for 10 days on your first time. That is safe and won't hurt anybody unless they dont drink water.
I usually run 500mg/day for 10-12 days, sometimes 750mg on the first two days. But ive used it many times and know my body pretty well and how I respond to it.
ALWAYS 2 gallons of water a day, and I throw electrolytes in each jug. (Extend BCAA mix by scivation is a good one), otherwise you can add salt, potassium chloride, and take calcium/magnesium/zinc supplements. Both wouldnt hurt.
Like insulin, it must be treated with caution. Take baby steps and find your sweet spot; don't rush it. DNP is an amazing tool, but just as deadly as insulin if used wrongly. Don't let that scare you, just be mindful and careful.