How can i make a Chat message for the server appear when a player touches a brick?

Easy. Insert a BinableEvent in ReplicatedStorage and insert a script into ServerScriptService for the event listener and insert a script into the part for the touched event.

Script for the part:

script.Parent.Touched:Connect(function(hit)
if hit.Parent:FindFirstChild("Humanoid") then -- Checks to see if a humanoid has touched part..
game.ReplicatedStorage.BindableEvent:Fire() 
end
end)

The script inside the ServerScriptService:

game.ReplicatedStorage.BindableEvent.Event:Connect(function()
         color = "Really red"  -- Color for the text
         game.StarterGui:SetCore("ChatMakeSystemMessage")
        Text = "This is a test" -- Change the text to what you want the chat to say.
         Font = Enum.Font.Gotham -- Font for the text
         FontSize =  Enum.FontSize.Size96
end)

Note that these are global variables..

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