My car makes this sound were it sounds like a trailer is passing by, when I floor the gas and when I let go of it, also when warming up?

Probably related to the exhaust system. A loose header (attachment from engine to exhaust) is possible. Older cars tend to get corrosion and looseness in the exhaust system that allows the car to "roar" louder than it should (sound makes it out through holes rather than passing through the muffler, which as the name indicates, muffles the engine noise). Rattling rather than roaring may be what you would hear, and that would be more an indication of loose attachments rather than corrosion of the pipes etc. Is your tail pipe hanging lower than it should or maybe even can be wiggled? (don't touch it when hot).

If it is just rattling that varies with how much gas you give, it is probably a detached hook or support somewhere.

Since you aren't very car-knowledgeable, you ought to see a mechanic and pay attention to what they explain (learn from them-make them explain and show you).

Just taking guess at sound, do you mean a roaring sounds or sort of a moan. If so, might just not have air filter housing latched down correctly. Has someone replaced engine air filter recently?

It sounds like a trailer is passing by? I have no idea what you mean by that. There are travel trailers, tractor trailers, utility trailers, boat trailers, etc, and they all make different sounds depending on speed, load, how rough a road is, etc. Try a better description. And why are you "flooring" the gas? There is very rarely ever a valid reason to do such a thing, especially when warming up a vehicle. It's not good for it. Being a girl is no excuse for being so clueless.