Commissioning of a wagon

So sports friends my problem is this: have a fiat fiorino(BJ: ca.90/91, 40kw, otto, hr:1116cm3). he stood for a good 1 year now in the fresh air without running in the intervening time. since I have almost no idea at all, I would like to ask you to tell me what I have to consider before I put it into operation. I have already looked under the hood. a few things rusted like e.g. the tube to the exhaust back. when I wanted to start it was battery empty and no oil in it. I heard that I had to drain the old oil and change the oil filter. on the other side I also heard that I should take off the ignition plugs and let crawl oil flow into the engine. but someone else said that you should have done that before the shutdown. please tell me what I have to do. which fluids I might have to replace. what else I have to control so that I don’t have to go half way. stay down. thank you in advance