I2S 2W Speaker Bonnet Pin Questions

[AlexMaghen]

I'm sorry if this is a little newbee but I've never worked with a "bonnet" or HAT before. 3 questions:

1. In the documentation for this lovely little thing, it shows me having to solder the 40 pin header on. But the one I just purchased has a low profile header already attached. Is that something new in the product? I just want to make sure I'm not missing something.

2. I am already using some pins on my RPi4 (which I'll be attaching this bonnet to). I apologize, but I'm not 100% sure how I'm supposed to best do that. Right now, I have an ultrasonic sensor attached with loose wires with female pin connectors to the following pins:
- 5v
- GPIO 23
- GPIO 24
- GND
To press the amplifier bonnet onto the RPi4, I have to disconnect these (obviously). Is the idea that after I press on the bonnet, I then solder (or connect, see question 3 below) the 4 ultrasonic sensor wires to the separate set of holes on the bonnet itself that sort of pass through to the Pi itself? Also, the numbering on those holes on the bonnet - are they GPIO numbers or pin numbers? Not sure I get that.

3. Is there something I can buy that allows me to push pins into these holes without soldering them - for temporary use while I'm experimenting? If so, a pointer to those things in the store would be great!

Again, sorry for the newbee-ness and your patient help is MUCH appreciated!

Alex