Larry. The basic thing is resistances sum, or divide. In series they sum, in parallel they divide.
Maybe a bit counter intuitively, daisy chaining is hooking the speakers in parallel. You aren't changing the connections, just running multiples together. The pluses are all hooked together, and the minuses are all hooked together. It doesn't matter if you string the connections from cabinet to cabinet, or hook them to multiple jacks on the back of the amp (which some PA and guitar amp heads have).
Series would be where the signal flows though each speaker to the next, using the speaker as part of the circuit. i.e. going from the + terminal of the speaker, through the speaker, out the - side and into the + side of another speaker, out it's - side and back to the amp. The problem with series connections is that if a speaker blows, it opens the connection and you have nothing out of anything, and in the case of a tube guitar amp which typically doesn't have the built in fault protection of a modern SS amp, leaving the output open while playing into it can damage the amp. For this reason you typically only find series connections as part of a combination of series and parallel. Most common example would be a four speaker guitar cabinet.
Now you may have already wrapped your head around the math of the 4 speaker cabinet. Four 8 ohm speakers if run in series would add up to 32 ohms, far too high. Run all in parallel it ends up at 2 ohms, far too low. So if you hook two speakers each in series, each pair would be 16 ohms (two 8 ohm speakers summing), then if you hook the two pairs together in parallel, the two 16 ohm pairs divide down to 8. Now you're back to your original 8 ohm load.
Impedance is basically the reactive resistance of something. A light bulb is mostly pure resistance. It doesn't do anything except resist electrical current flow and use that resistance to create enough heat to generate light. But if you could imagine the instant of turning it on, the cold wire has less resistance than it does when it's hot, so for that brief moment, the resistance rises while the electricity is going though it.
In a speaker, there are bunches of things going on. Mainly, you're using the electricity to yank a mechanical cone back and forth. Basic Newtonian laws say that something put in motion wants to keep going that way. Then you are trying to reverse the electricity and yank it back. So for a moment it acts like a generator and then it sucks extra electricity to reverse it’s direction. Then once it gets going, it doesn’t need as much power to keep going, until you try to reverse it again.
All this means that the amount of resistance, or load, the speaker shows to the amplifier’s output, varies all the time. It isn’t pure resistance. And it varies with frequency depending on things like the strength of the magnet, the weight of the cone, porting on the cabinet which resists the cone’s moving at some frequencies and provides no resistance at all at other frequencies, and many other factors. Typically the average impedance is what is written on the speaker and what people go by, unless you are a speaker designer and trying to get all the factors to play well together.
Back to your question of running your amp in bridge mode. The basic thing to remember is that bridge mode halves the load on the amp. So if you run an 8 ohm load on a bridged amp, you are actually running the amp at 4 ohms. This is because in bridge mode, each channel of the amp is acting on one half (either the positive or negative swing) of the signal.
So, in your case, if you want to hook two 8 ohm speakers to your amp in bridge mode you have to first calculate the speaker load. 8 ohms divided by 2 speakers leaves 4 ohms total load. Then you halve that for bridge mode, leaving a 2 ohm load on the amp. Looking at the attached data sheet for the amp, it is rated for a 2 ohm load. It also lists a power output into a 4 ohm load in bridged operation, meaning to finally directly answer the original question, it is okay to hook two 8 ohm speakers to it in bridge mode. In fact, that gives the highest power output.
Now, if you daisy chain more than two speakers, you have to recalculate the load. E.g. if you have three 8 ohm cabinets, 8 divided by 3 gives 2.6 ohms. Since the amp is only rated down to 4 ohms in bridged mode you can’t daisy chain 3 cabinets to it. But each channel running normally is rated down to 2 ohms, so you could run 3 cabinets off of one channel.
There is some debate in the pro sound community on using bridged operation however. One side wants more power. And there is engineering math to justify running around twice the amplifier power into a speaker’s rating to optimize performance (e.g. 1200W amp into a 600W rated speaker). So when you have 2000W speaker cabinets, you kind of need to run amps in bridged mode to get the 4000W that would optimize their performance. But running flat out in bridged mode (like at a large concert, not what will happen at your corner bar with a band, DJ’s are another kettle of fish altogether) means that the amp is passing all the electrical current it can. Meaning it will run harder and hotter. More distortion and less reliability, which means something at the varsity level.
Now I hope you’re thoroughly confused.