You will enter this as self-employment income. You will need to file a Schedule C and pay SE taxes. You may also enter any expenses related to your work to reduce your income.
To file a Schedule C, here are the steps:
Sign in to your account and select Pick up where you left off
At the right upper corner, in the search box, type in schedule C and Enter
Select Jump to schedule C
Follow prompts
Below are a couple of links that might be useful to you.