How do I get in?

Into "what?"

how can I use Turbo Tax?

Are you asking how to start a new online return, or do you want to purchase the desktop software (CD/download)?

How do I get started?

You choose a product on the page I gave you below and click the "Start for Free" button.  Then follow the prompts to set up an account if you don't already have one, or to use the blue "Sign In" button (top right corner of the create-account screen) if you do already have one.

The online products are shown on:
https://turbotax.intuit.com/personal-taxes/online/

Choose the edition you want, and click the button "Start for Free."

See the screen image below: