Bangle.js wont connect

Sorry for the delay - I've been on holiday last week.

Glad you got it sorted - odd about your phone though. What model is it?

after the Default Apps have been installed, how much memory is left for additional apps to be installed?

A lot - I think the default apps take something like 0.05MB and there's 4MB on the watch. The biggest issue is RAM usage if you want to have lots of widgets running at once.

One last question, how to set the time from 24 hour to 12 hour time.

Settings -> Locale -> Clock Style should do it, although it depends on the clock. Most should use that setting, but some don't.