I've just started learning about electricity as I've just recently started to learn electronic engineering online. Right off the bat I'm hit with confusion. I understand that conventional current is that positive charge runs from the positive end of the battery to the negative and that electron flow runs from the negative end of the battery to the positive, both of which via a conductor such as a copper wire.
First thing to note is that in the way they're initially introduced in a textbook, these effectively represent two different ways of looking at the same thing. IIRC, conventional flow has it's name because intuitively we just assumed that it would be a "positive" or "noninverted" charge making electricity work. Eventually we found out that it's electrons that actually travel around a circuit. An electron is an electron, and an absence of one is referred to as a hole. Especially as you're starting to learn, it's probably best to work with electron flow and remember that conventional flow diagrams exist, just in case you run into one. Edit: In electrical(electrician, not ee) school I was taught that conventional flow is obsolete and should be phased out. I've since found out that both are still widely used, with textbooks being printed in both.
That said, there is an apparent fundamental difference in mobility between N and P type semiconductors. I'm not well informed about this, but as I understand it, the reason P mosfets are slower(have higher gate capacitance) than N ones has to do with holes being used as a carrier and having less electron (or hole) mobility.
A) Am I correct that both flows happen simultaneously?
Yes. These are just two different ways of looking at the same thing. Electrons are the only thing moving around, and places that are absent electrons are holes.
B) If I place components on the circuit, say a resistor close to the positive end of the battery followed by an LED, e.g. and if I switch the place of the resistor to be on the other side of the circuit, e.g. do both of these work? If so, how?
Changing the order of a series arrangement like this as you have won't have an effect on the circuit because the same current flows through both the resistor and the LED. I didn't initially notice that you'd also changed the direction of the diode, which will change the direction in which it resists current flow.
In my mind I rationalise that surely electricity can only work by travelling in one direction, linearly through a path, but apparently it happens in both directions?
For current to exist, electrons must be moving in a single direction, and they flow from high voltage to lower voltage. But sometimes, for most power transition for instance, the direction of pressure and current is alternated, and this is what is referred to as AC current. One simplification I find helps most people is to think of the electrons as a fluid and the conductors they travel through as pipes and devices.
How then do you construct a circuit if your power is coming from both directions?
Sometimes you want AC specifically rather than DC. There are far too many ways and reasons to take advantage of AC or DC electrical systems to mention here.
In my first schematic above shouldn't the LED burn out due to the electron flow not passing through a resistor first?
No, the same current flows through devices in series. Now for the obligatory textbook mentions. If you read up on Voltage, Current, Ohm's law, Watt's Law, Series and parallel resistance, Kirchoff's law, you'll get a good start on understanding simple circuits.
C) Do both positive and negative charges' power provide equal amounts of power to a component?
P=IE, which is to say power is equal to voltage drop multiplied by current, in a purely resistive circuit (inductance and capacitance complicate this a bit, creating reactive power, which is stored and put back into the circuit). Some devices, such as diodes will only allow current to pass through them one way. and many devices cannot operate if voltage is reversed, but all other things being equal, the same current passing over the same resistance will use the same amount of power.
D) if current runs from both directions out of the battery then does it matter which direction the battery is facing? Could I just flip it around without any consequences?
No, directionality has been discussed, but to be clear many devices will malfunction or be destroyed if DC is connected to them backward, while other devices can be designed to be extremely tolerant. AC on the other hand alternates at ~50-60Hz, so most AC devices function just fine when connected backwards, however polarized plugs exist in order to protect some AC devices from reverse connection.
I hope my beginner level questions don't frustrate people. I've just been trying to rack my brain around this over the last few days. I unfortunately do not have a teacher to ask these questions to.
No worries, I think a lot of these get removed for being too broad or lacking research. I think in this case you probably just need an idea of where to start reading. Fair warning, you can't skip a lot of steps in learning about this stuff and it can be hard to know what to learn next. You can do a lot of hobby stuff without going so far as using calculus, but expect to regularly use basic algebra.