i there,
So,
I get a strong inklings from your Questions, you didn’t go through the tutorial or watch the video Then 
. I won’t spoil it for you 
, He directly answers your question, Suffice to say " you put the model in “continuous mode”
Funny part is, That one is the easiest and the most full featured models and training tutorials if YOU 
do the work…
It all Works. Longest part is building the Data sets, the Hello_world, Yes, No. (unknown) and NOISE (everything else).
You can use the MIC on the Board. BTW. or Phone or Xiao PDM.
Easiest I found is to use the Board’s Mic. Mobile phone ,Next and Xiao you load a recorder IMO, record the PDM , 16-bit samples and save them to SD and upload to the EI KWS training model as Set data.
Once it builds, you verify it works , then grab the C compiled BIN or HEX , You load that on your device, Then connect to the serial port of it with computer terminal and Power it up, You can make it boot the code or , kick it off with a terminal command. 
I may do a video Walk through with a Xiao, Time permitting. but it is very, very similar in steps and process as the object recognition demo I did a while back on here. Stuff is AWESOME 
Here is the Missing LINK in your Evolutionary understanding 
Watch the WHOLE video!
Run through the How to and LMK were you get stuck.
HTH
GL 
PJ 
Here was a Thread we walked through the Bootloader restoration…:fingers