Once you join a channel that doesn't previously exist, then the channel is created and you are granted ops status in the channel.
At this point, I highly recommend that you register the channel with whatever channel service the network uses (most common is chanserv).
Also, at this point, you have Founder abilities, which can only be overridden by someone with IRCops status, which is granted to specific people on the network to control the entire network, not just certain channels.
For a channel, generally speaking, this is the list of accessability from highest to lowest:
Founder
Admin (not applicable to all networks)
Op
Half-Op (not applicable to all networks)
Voice
Regular
Someone with a higher access has all of the abilities of those with a lower access.
Note: IRCops have different levels also, and all of them exceed the level of Founder.
These levels (listed like above) are:
Network Owner
Co-Admin
Services Admin
Server Admin
HelpOp
Some networks may have other levels, but as far as your abilities on a channel that you have created, this is irrelevant, just posted for general information.
