1. You should plug it into its own individual socket on your wall outlet but you may have other things plugged into the socket below it. I have a Lasko heater plugged into the top socket of my outlet and I have a surge protector, with my TV equipment on it, plugged into the bottom socket. Just make sure you don't plug the heater into an adapter or a surge protector.
5. Heaters such as these require a great deal of power (up to 1500W): Your breaker may not be able to handle anything else which uses significant power--while running at the same time and using the same circuit. It's probably OK merely to have such things plugged in, too--given that they aren't on/active. It's best to use a bare, separate outlet, though.
Refrigerators, washers, other major appliances, microwaves, toaster ovens, A/C window units., hair dryers, heat guns, power tools, desktop PCs, laser printers, etc. require a great deal of power (wattage), too--similar restrictions apply to them as well.
Some space heaters here use 12.5 amps--that's a little more than an older, old-school vacuum cleaner--using 12 amps. This heater has somewhat higher wattage though and the related current likely is akin to 15A--that's equivalent to better quality consumer-level circular saws, table saws, etc. I'm now looking at an old, used-up power tap: It indicates that 16A was its maximum limit. So, the limitations of a power tap, which generally did provide a great deal of power to devices, should tell us something concerning the limitations of home wiring--a rough idea of what the wiring was intended originally to provide. Invoking a space heater is a special use of your home's wiring.
Your clothes dryer uses a 230V+ heavy-duty outlet--far stronger than most other home outlets: That's very telling about your dryer, isn't it?: Certainly, it uses a separate circuit. As space heaters are, clothes dryers prove specialized and powerful at heating--incidentally, they dry clothes very well. Note how the dryer forcibly is dedicated to a single, powerful circuit, though. The home dryer is used very often: Thus, the building code provides that particular and wide margin of safety. The code assumes also that the home's heating system should prove solely sufficient--limited allowance thus is left over for portable space heaters--especially if the the user isn't cognizant of proper use.
Your circuit breaker or GFCI likely will trip if you run multiple power-hungry devices at once, using the same circuit--say the toaster oven and the microwave (which I did inadvertently a few days ago): That's a warning--the circuit breaker is doing you a great favor. Be cognizant of your power limitations and thus overloading your outlets/circuit breakers when using power-hungry devices--as space heaters are....