2001 Ford Windstar Won't idle, knocking, smoke

The other day, while running errands my fuel light came on so I stopped and put in almost 3 gallons then drove home. The next afternoon, almost 24 hours later, it wouldn't idle, kept dying. The fuel light was on so I added gas, 3-4 gallons. It still wouldn't idle. I thought maybe I had to run the fuel through the system so I sat and ran it with my foot on the gas pedal. Then when I revved it up to 4000 rpms, I heard a knocking (sounded like it was behind me), shortly after, I smelled hot and a tiny bit of smoke was coming up from under the hood. I didn't see where the smoke was coming from.

Next, I noticed my coolant reservoir was empty or near empty. So my question is, if I add the appropriate mixture of coolant/water, can I try starting the van or should I get it to a mechanic and NOT try starting itmyself? I don't want to blow a head gasket or ruin the engine in some other way by trying to start it. Thanks!