A couple months ago I started working in a store. The training portion is over. The store recently had a lot of turn over (even for retail). Aside from the manager, the longest employee has been there for 5 months. He is extremely bossy towards me and its really getting on my nerves. To be clear, he is in no official capacity my boss. He is not a supervisor or a manager.
He frequently gives me lists of things to do. Yesterday just as I arrived he said "take over, I'm going to the bank". Just the way he says and does these things sounds really domineering. I think this may be his first job. Hypothetically I could just do what he tells me to do but I think the expectation I have with management is that this job is done more autonomously in that employees ascertain for themselves what needs to be done at an individual level. With the other employees we sometimes ask each other for help to do a task which requires two people (which there aren't many of). But just telling me to do something by myself is different. If nothing else, I have difficult reading his short hand in the lists he gives me.
Also somethings he tells me to do, I can't possibly believe are right. For example when we get an online order for pickup (e.g. Door-Dash) he tells me to hit confirm right away even before we check to see if we have the items in inventory.
What are some ways I can try to address and change this behavior? I'm considering saying "I'm about to do x, why can't you do that?". It's the same person who had asked me to stay late.