Here is little info, hope it helps:
(1) how do I know what is the LUN ID.
-> Depands on the driver which you are using.
for example: if using linux native multipathing then "multipath -ll" will...
If you are new to Linux, then it is suggested that you 1st clear the basics instead of directly jumping to the Commands. The guide in above post or any other book like complete reference.. etc will...