Low cost gateway and sodaq one

Hi all,
Excuse my silly questions, I’m really new at LoRa and still trying to wrap my head around it.
I’ve build a gateway using a Raspberry Pi and RFM95W using this site

I’ve loaded the GPS tracking sketch in the Sodaq one and get the GPS co-ords, temp etc and I get a transmission successful on the Arduino IDE, but I don’t see the message on the Gateway. I have a couple of questions please

  1. Do you specify a channel number and frequency on the Sodaq one, if so, how?
  2. Is the gateway I’ve build “compatible”
  3. On the base one board, there is a power switch with no ON OFF markings, what does this switch do?
  4. I’ve connected a Solar panel and lipo battery, how do I know if it is charging?
  5. In layman’s terms, what is the spreading factor?