how do I export ConEmu settings?

Latest versions has Export button.

Where_settings_are_stored?

Exporting settings

reg export HKCU\Software\ConEmu ConEmu.reg

Importing settings

reg import ConEmu.reg

When you are using portable mode, ConEmu.xml file may be located near to ConEmu.exe or ConEmuC.exe.

Note Portable mode doesn't suppose installing in %ProgramFiles% (x86 or x64). Obviously, ConEmu requires Write-access to ConEmu.xml if you want to change settings, store history, autosave windows size/pos on exit and so on. However, if you like fixed configuration and don't suppose to change xml file in any way, you may use %ProgramFiles%, run ConEmu first time "as Administrator", set up your configuration and Save settings (don't forget last step). After that you may run ConEmu as ordinary user with read-only access to xml-file.