I'll take a shot. The subtitle of the essay is "Doing Words with Things", which is a reversal of the famous essay of John L. Austin "Doing Things with Words".

I'll take a shot. The subtitle of the essay is "Doing Words with Things", which is a reversal of the famous essay of John L. Austin "Doing Things with Words". Austin pointed out that words have practical effects. Consider the speech act 'I do', when two partners marry: it are the words that have a specific effect in real life. Now Latour claims that we -- philosophers, sociologists, but others as well -- have to pay attention to the effects material objects have on people interacting with them. He claims that a specific way of acting can be inscribed in an artifact. So the key is an example of this: you can only take your key out, if you lock the door behind you. Rather than having a message next to the door saying "Please lock the door behind you", this type of behaviour is enforced through the artifact itself. So social mores or norms can be inscribed in and enacted through material objects (and not just through words). At least that's an ELI5 version of what the essay intends to convey.