I cant play animations in my characters?

Well, I assume you've already made your animation and a LocalScript with and Animation as a child. For example it should look like this:

StarterPack
    -LocalScript
            +Animation

(I won't make the whole script for you because you've shown no effort (proof) that you've tried scripting. This is not a requesting site.

wait(1)

local player = game.Players.LocalPlayer --You need to identify the Player
local Mouse = player:GetMouse() --You obviously need your mouse for the KeyDown function
local humanoid = player.Character.Humanoid --Humanoid
local s = humanoid:LoadAnimation(Animation) -- Put the LOCATION of your animation here, for instance, if you have your animation INSIDE of a local script in StarterPack, then you'd put (game.StarterPack.Localscript.Animation)

Mouse.KeyDown:connect(function(key)

-- code

end
end)

I hope I helped!