How do I make an animation play while another one is already active?

I made a crouching animation for a game I'm working in which you hold ''c'' your character gets in a low position and their walk speed is slow. I have already made a walking animation for it where if you try moving while you're in that crouching position only your legs move, But I can't find a way to implant that crouch walk animation into the game. Any help?

Here's the crouch animation:

local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
local Animate 
local Humanoid = player.Character:FindFirstChild('Humanoid')

mouse.KeyDown:Connect(function(Key) 
 if Key == "c" then
  local Animation = Instance.new("Animation", player.Character)
  Animation.AnimationId = "rbxassetid://02633068545"
  Animate = Humanoid:LoadAnimation(Animation)
  Animate:Play()
    Humanoid.WalkSpeed = 5.5

 end  
end)

mouse.KeyUp:Connect(function(Key)
 if Key == "c" then
  Animate:Stop()
    Humanoid.WalkSpeed = 16
 end
end)

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Video of what the crouching animation looks like: https://gyazo.com/d427b29ec06f88429bea89ea5f26c6c8