How would you use a mouse to select players when clicked?

How would you select a player, when you click on the player? And I'm thinking of also asking about how you would make it push the player backwards, and an animation pop up on you.

It depends what you mean by "Select a player."

To start out, if I were you I would probably write a script to insert a ClickDetector to each of the Player's limbs when they join the game, then write a script that detects when the ClickDetector is clicked.

function assignClick(Player)
ClickDetector = Instance.new("ClickDetector")
p = game.Workspace.Player:GetChildren()

for i,v in pairs(p) do
	if v:IsA("Part") then
	ClickDetector.Parent = v
	else
	return
	end
end
end

game.Players.PlayerAdded:connect(assignClick)

That script should assign ClickDetectors in each of the Player's limbs.

noooo i would not use click detectors. I would use the mouse in a LOCAL script.

local p = game.Players.LocalPlayer
local m = p:GetMouse()

function showprofile(player) -- change this to a gui, or whatever
print(player.AccountAge)
print(player.userId)
print(player.Name)
end

m.Button1Down:connect(function()
local target = m.Target
if target and target.Parent and m then
if game.Players:GetPlayerFromCharacter(target.Parent) then
showprofile(game.Players:GetPlayerFromCharacter(target.Parent))
end
end
end)

using the mouse is a lot easier and cleaner than using a click detector.