Your Stellar account will be locked on ICO period which means You can view and receive tokens but can't withdraw. The account will be unlocked automatically after ICO ends. So You will not have to unlock it manually. But if You want to unlock it manually, please follow this instruction below (please note that it will not work if You try to unlock Your account earlier ICO end date).
Navigate to Stellar laboratory page, paste Your unlock transaction data (You get it when buy tokens) to field "Transaction Envelope XDR" and click Submit button:
You should end up with the following result (some values will be different as You transaction data is different but the structure is the same):
In case You submit unlock transaction too early You will receive the following response:
So please wait until ICO ends and use unlock transaction in case withdrawals from Your account remains locked.