The listing, 0.001 Bitcoins has ended.
0.001 Bitcoin delivered to you wallet, just send me address.
If you need to know how Bitcoins work see:
https://bitcoin.org/en/
I recommend using either the wallet on your coinbase.com or the Electrum wallet, so you need not store the whole blockchain on your local computer. The blockchain is a record of every transaction that has ever taken place with Bitcoin, which is ~140GB in size.
Regarding using a coinbase.com account. In the past experts have advised against online accounts because they were getting hacked all the time and coinbase owners were losing their coins. An established site like Coinbase would seem to be safe but safer still is offline storage in a wallet like Electrum.