Jumper wire goes in #6.

Do that with the key off then turn key to fully on but do not start engine..
Press the button for 1 second and release.
Count the flashes example 2-3-2 it flashes 2 times then a pause then three times then a pause then 2 times.
Now press the button again to get the next code. If there are no more codes or if there are no fault codes you will get 1-1-1

The codes wrap around so if it has multiple codes it will come back to the first code after multiple presses. You can get a list of codes online, from several sources.

Write down the codes in case you decide to reset the computer. After 89 the ecm fuse is to the left of the coil a 25 amp blade fuse that you can pull out for a few minutes and then replace to reset the computer. Resetting the computer does not fix anything but if you had a battery problem or flooded the car it could have created a false code. You will know within a few driving cycles then get a check engine light or do another code check and get same codes back.

If you place jumper in #3 you can pull codes from the fuel computer, which resets in the same way.

You can reset codes from the button but in my experience the fuse removal is easier and less frustrating.