Right click anywhere on the screen (Chrome browser only) and click Inspect.
In the window that appears on the right, click Application on the top bar (you may have to click the dropdown arrow next to Elements, Console, Sources...).
On the left, navigate to Storage > Cookies > http://fantasy.espn.com.
Scroll down in the table to the right until you find SWID. Copy & paste the alphanumeric string in the the Value column (without the curly brackets).
It should look something like: 43B70875-0C4B-428L-B608-759A4BB28FA1
Next, keep scrolling until you find espn_s2. Again, copy and paste the alphanumeric string in the Value column. This code will be much longer and won't have curly brackets in it.