First, click on "Choose" and you will see a list of the known volunteers. Scroll down until you find your name and click on it.

Second, click on "Hours" and scroll down until you find the number of hours you worked and click on that.

Finally, click submit (the green button at the bottom) and your hours will be recorded. Note that if you made an error and need to amend your entry, only the final entry for each date is retained. For example, if you make two entries for the same day, one for three hours and a second entry later for two hours, only the two hours will be recorded.