This is what I did:
1) Downloaded the clam client. It was taking forever so I downloaded the block chain snapshots. This took a few days.
2) Emptied out my Bitcoin wallet (transferred all the coins to my Trezor hardware wallet).
3) Imported my Bitcoin wallet into my Clam wallet.
4) Got a few clams because some of the addresses in my Bitcoin wallet had value on the distribution date.
Pretty easy.
There is a lot of information about this if you just search for it. Try Google. That is the search engine I use.
why only on that particular day there is a reason behind this?
Because it is by far the fairest and most efficient way to create an initial distribution of coins. If you have an idea for a better way you can, of course, create your own coin using your method.
yeah i searched before posting, and on reddit they don't mention that you only get the coins from the 12th of the month of may, but you get everything prior the 16th of the month, look at this