wireless transmission

I am working with the HC-12 Wireless module for a quite while.
When reading about changing its baud rate, channel, etc I got some doubts.

I don't understand the concept of channels.
if the channel is different between two communicating module can they still communicate
is it like the frequency of transmission changes
when the channel is changed is it like the entire different program is used

Also about the relation between baud rate, speed of data transmission and distance.
Like how are they propotional or inversely propotional.

Thanks in advance.

PROBOT135:
if the channel is different between two communicating module can they still communicate

No. both transmitter and receiver need to be on the same channel. Channels are a way to have multiple modules communicating without interfering with each other

is it like the frequency of transmission changes

Yes. It is that. Each channel is 400kHz away from its neighbor

when the channel is changed is it like the entire different program is used

More like an entirely different frequency for transmission/reception is used

Also about the relation between baud rate, speed of data transmission and distance.
Like how are they propotional or inversely propotional.

Don't know for sure but this article has a nice chart about it