Ill break it down for you if you don’t understand it then.
-- Entire code
local test1 = script.Parent.Touched:Connect(function()
print("no")
end)
scipt?Parent.Touched is a RBXScriptSignal. It is an event which is fired everytime the part it touched.
RBXScriptSignal has a function called Connect which returns a RBXScriptConnection you also have to pass in a function as the argument
Touched:Connect(<insert function here>) -- Returns a Connection
To read more on the subjects I highly recommend you go to the devhub and search the terms in as you get a much better way of understanding how events work.
The value stored in the variable is a RBXScriptConnection. It can be disconnected if it is no longer needed.