If you want to use it properly you should know about different factors of it. If you open the google adwords, you will find a window. At the top of the window you need to select the keyword tool.
Then you will see the blank space for typing your niche and you can use many of them at a time by using ENTER here. You will find also some options as like Category, advanced options , you need set these as you like.
In the left portion you will find a option named "match type", you can choose them by your need. You can choose "phrase", if you need to find long tail keyword. You can choose them all at a time for getting better result.
In the right portion you will find a option below the"about this data" named "columns". There are many important options for you. I hope if you try this. This will help you to find good keywords for your blog. Let me know if you need anything to know about it.