how can I create a block chain? How can I reate a block chain and a bitcoin wallet as I want to start trading in bitcoins.  I have never opened a bitcoin waller or block chain and am not sure if I should have both?
A blockchain is the basic data structure used to record the transactions in the network. It already exists, you don't need to create it. This is like asking "I want to send an email, how do I create an internet?".

You need Bitcoin wallet software. See https://bitcoin.org/en/getting-started for more information.