-1) Remove the old App via setting......Application manager...Uninstall Steam


-2) Download steam app from Appstore or GooglePlay
On Samsung: It is Play Store

-3) Log in with the phone app. However, this time select this:
A) No longer access to m codes
B) Use this device (If you don't have cellphone, your recovery code will come in handy here)
the code will then be texted to you
Note: I believe it has to be the same phone number stated in your account security. Otherwise, you lose the steam guard.
do NOT select disable autheticator. Otherwise, you get 15 day hold
-4) okay send me the codes (It will be on this phone which is same as before)

Note: I believe it has to be the same phone number stated in your account security. If the phone number changes, you lose the steam guard.