I've updated my last fire script, but how do I refer to parts of the players, such as their health?

I recently asked a question about why my fire script wasn't working, and I got some help. However, I now have an issue where am not sure how to properly refer to parts of the player in the script. I am trying to make a script where when the player approaches the fire, they start burning, but now am not sure how to access their health.

local firePart = script.Parent

local Players = game:GetService("Players");

firePart.Transparency = 1

local function LightOnFire(part)

local fire = part:FindFirstChild("Fire")

if not fire then

fire= Instance.new("Fire")

fire.Parent = part

local client = Players:GetPlayerFromCharacter(part.Parent)

if (client) then

Players.

end

end

end

firePart.Touched:connect(LightOnFire)