Each polarisation from each antenna is processed by a separate channel. The electronics on this channel is called a Receiver Unit (RCU). KAIRA has 96 RCUs (numbered 0..95).
When looking at the signals coming into the system, they are labelled by their RCU number in the first instant. One needs to map this to the antennas to work out which antenna/polarisation is being shown.
The polarisation mapping is straight forward... even numbers for X-polarisation and odd numbers of Y-polarisation. However the match between the RCU numbers and the antenna numbers is a bit more confusing. Yes, there is a logic, but it is not obvious. Sometimes it is simply easier to look it up!
So, here is the mapping of RCU to antenna number for KAIRA (the scheme is different for other LOFAR stations).
For where those antennas are on the actual site, refer to the array layout map.