It take me few minutes to download the client (4 mb only).
4 to 5 hours to 100% sync with the blockchain for the first time.
Download the windows client here .
https://www.antshares.org/en-us/download1) Unzip, Open and run AntSharesUI.exe.
2) Go to wallet --> Create new wallet database. Key in your wallet name and password. Save the .db3 on your pc. You will need to browse the file and key in password everytime opening windows client.
3) On the bottom left, it will show height 1067220/1067220 ( This is the current 100% sync ) The number will increase as time goes on. Make sure both number is identical to have 100% sync. It take about 4 to 5 hours for the first time. Be patients
4) On the account tab, you will see your standard wallet address, it will show ANS and ANC balance. Right click on the address to view private key and mark in down on piece of paper. You will need this private key to restore your address if you lost existing .db3 file.
5) To restore address --> Import from WIF --> key in your private key.. Your address will appear there. Let it sync a while to reflect your antshares balance.
6) Transfer antshares from Bittrex to your standard account address. The transfer is almost instantaneous. Your antshares balance will be reflected.
7) To claim antcoin, go to Advanced --> Antcoin Claim . You will see Available 0 and Unavailable XXX amount but you can't press Claim All. Don't worry.
8) The next step is to send antshare back to yourself. It doesn't cost any fees.
Go to Transaction ---> Transfer --> Press the +. Payment window will appear. Choose Asset as Antshares, put your standard account address, total amount to transfer, Press OK and you are done.
9) Now repeat the step 7 to claim antcoins. You should be able to press Claim All. Your ANS and ANC balance will be reflected in Accounts tab.
Happy trying

Can explain the reason for step 7 to 9? I mean isn't the coins already in my standard account? Why still need to transfer into the same address again? I tried doing what you said and it works. I just don't get the mechanics and reasoning behind these steps. Thanks in advance for your clarification