How do i daisy chain two ur824's?

I have tried to connect using optical cable out of the slave adat into the master adat, i get no signal in pro tools.
Im sure i am doing something wrong but cant seem to work it out.
Any help appreciated!

I have no idea what you mean. What do you mean by slave ADAT and master ADAT? On the UR824, there are 2 ADAT inputs and 2 ADAT outputs. Each input and output are labeled as A or B. Your main interface will always be the central point of connectivity, meaning you can send digital output signals via ADAT output A and B and can receive digital input signals via ADAT inputs A and B.

All other devices can then receive those ADAT output signals, or send their own ADAT output signals into the ADAT input signals of this main interface.

Please explain what you are trying to do again.

You need to route the analog inputs to ADAT outputs. In the DSP mix utility set the appropriate ADAT out assignment to the Analog In that you want.