The best way to go about submitting Timesheets is by the Crew Member who created them, in the Mobile App. But if you're in a pinch and just quickly need to submit a time card or two so you can export them all to QuickBooks, you can also do it from the Web App.

Here's a tutorial:

Go to Time in the main sidebar.

Turn on the toggle to Include Unsubmitted timecards.

The exclamation point icon to the left of the time card tells you that the time card is unsubmitted. To submit it, click on the In and Out times to the right.

This generates a popup with editable fields. Change the Status field to Submitted and hit Update.

You will see the exclamation point icon disappear and you can now export this time card. If this is your first time exporting, here's a tutorial for exporting time to QuickBooks.