How would i make this happen whenever a player joins or respawns?

Here is code that may help you:

local PlayerService = game:GetService("Players")

local function onCharacterAdded(character)
    --Run respawn code here
end

local function onPlayerAdded(player)
    --Run join code here
    player.CharacterAdded:Connect(onCharacterAdded)
end

PlayerService.PlayerAdded:Connect(onPlayerAdded)

What it does: it gets the service called Players and then connects an event called PlayerAdded under Players to a function we made called onPlayerAdded. Then, in the onPlayerAddedfunction, we use the playerinstance obtained by the playerparameter included in the PlayerAddedevent to connect an event called CharacterAdded, which is fired when the player's characterrespawns, to a function we made called onCharacterAdded.