Connect your Etrex to the computer via USB and wait for it to be recognized and mounted. Then select Your Profile, Field Notes from the GC main menu and then select Upload My Field Notes. Then you just edit and post your field notes from the Field Notes screen. This gives you the chance to correct spelling, embellish the descriptions, etc while on the computer with a keyboard and not entering logs with the thumb stick.
Do you have a smart phone? You might want to look at some of the free geocaching apps available for iOS or Android. I only mark the find as Found on my Etrex and then use an app on the smartphone to post a field note or actual log right to the web site while I'm in the field. I find that a geocaching app and smart phone makes a wonderful complement to the Garmin while I'm in the field.