Hi
Setup everything as you will use keyer and paddles, and check that it works. Then activate "Keyer" on input 0 in the Control RRC IO-menu. Connect the straight key to input 0 in the I/O RJ-45 connector, see manual for pin config.
If you just use I/O for the straight key you can not use the key delay, and your CW may be disturbed by jitter on the internet.
73 de mike