How can I find a player from his character?

Many ways first if we were to do it via LocalScript in StarterGui or StarterPack the script would look like this:

Player = game.Players.LocalPlayer --Sets the LocalPlayer
Character = Player.Character --Sets the Character

But this is only for LocalScripts what if we would want to run it from a Touched **event via **Script?

Hierarchy: game > Workspace > Part > Script

script.Parent.Touched:connect(function(TouchedObject) --Creates Touched event function
    Character = TouchedObject.Parent --Sets Character
    if Character then --If Character is TouchedObject.Parent then proceed
        Player = game.Players:GetPlayerFromCharacter(Character) --Gets Player from Character
    end
end)

There are also ways to do this via ClickDetector:

Hierarchy: game > Workspace > Part > ClickDetector > Script

Clicker = script.Parent --Defines ClickDetector
Clicker.MouseClick:connect(function(Player) --MouseClick event function
    Char = Player.Character --Gets Character
end)

Then there is of course the PlayerAdded/**CharacterAdded **events

game.Players.PlayerAdded:connect(function(Player) --PlayerAdded event
    Player.CharacterAdded:connect(function(Character) --Character Added event from Player
        print(Character.Name)
    end)
end)