First I buy HIVE or exchange my HIVE Backed Dollars (HBD) into hive. If you don't have HIVE, you can use Blocktrades.us to get some.

Once you have HIVE, head over to the LeoDEX. You'll have to then use your Keychain to move HIVE to the exchange. Then you can bid using your HIVE to buy LEO.

You're also already starting to earn some which will payout 7 days from when you published this post. Congrats! Hope this helps.