Stupid questions about the LimeSDR

The LimeSDR has several antennas (txrf1_a, txrf2_a, txrf1_b, txrf2_b, rxrf1_h, rxrf1_l, rxrf1_w, rxrf2_h, rxrf2_l, rxrf2_w), how to know which one to use, in osmotrx for example?

How to use the clock antenna? Does a GPS module exist?

LimeSDR is powered by the USB port, what is the port used for?

Thanks for your help.

are you referring to the datasheet for LMS7002M or are you referring to one of these development boards:

thank you for your reply,

I asked too quickly, I should have taken the time to look a little. It is to understand the operation but I think I will buy the mini.