Welcome to Android Central! If you're using the Gmail app, open it, swipe in from the left, and tap the little down arrow next to your name. Now tap Add Account, select Google, and tap OK. Proceed from there to add the other Gmail accounts.
i followed suggestion by swiping from the left to locate dropdown arrow next to my name; however, there is no dropdown arrow. there is a check mark. any other suggestions to add another gmail account to the gmail app?