Very simple use of multiple HC-05 slaves?

[J-M-L]

@walshrd

Not sure if an antenna is required if
transmissions are to be within a large room only

the spring antenna that ships with the module is good enough. Goes quite far

google will give you tons of tutorials and experiments, here is one

Arduino and HC-12 Long Range Wireless Communication Module

once configured (which you can do once outside your app), it's really just a serial communication