The speakers you are using have a maximum power draw of 6 watts. That's not going to be very loud, and the speakers are VERY small, so don't expect great sound out of such a product.
That said, because they only have a maximum tap of 6 watts, that means 8 speakers can pull a maximum power of 48 watts (6x8=48).
A 50+ watt 70v amplifier is plenty of power to drive the show here, and there are plenty of used options on eBay for really solid commercial amplifiers for not a lot of cash.
ie:
https://www.ebay.com/itm/284552585034?hash=item4240a7df4a:g:nigAAOSwY2NhqRiN
You don't need any speaker distribution system, as 70v systems are designed to just be connected together.
So, you return the speaker selector, and you return the Pyle amplifier.
You will need a source and you should be using a decent source/mixer if possible, but it's not required. But, you will need to follow some Google-Fu to get things wired properly if doing it yourself as most 70v amplifiers want a professional balanced input into them. If you are using a source with an RCA output, then you will need to connect it properly. While you could just buy a Extron CSR-6, which may make the most sense if you aren't experienced, to get RCA inputs into the amplifier, you could also make it for about $5 if you can follow basic wiring instructions.
I'm not sure even with a proper amplifier how much volume you can expect out of cheap 6 watt speakers. It will depend on how large your space is and how much volume you are hoping to achieve. At about $30 per speaker, these really are scraping the bottom of the barrel, but the Extron amplifier was $500+ when new and is NOT a product which scrapes the bottom of the barrel.
You definitely aren't using the right combination of equipment at the moment, most notably that Pyle amplifier is not proper for the speakers in place and distribution is not needed.
That said, considering the wrong equipment is in use, I'm not sure if things are properly wired either.