In Gmail, we recommend deactivating the smart inboxes to go back to having all your new email in one spot. This is done in Settings and then Inbox .
“If you are using Inbox by Google, the setup is similar to Gmail. Even though you could achieve a ‘smarter’ version using the Snooze feature we still recommend working with Labels to sort your email quickly by hand.”
In Gmail keyboard shortcuts need to be turned on before you can use them. This is done in Settings right under the Desktop Notifications (see image above).
In Gmail folders don’t really exist. They are called Labels and do not really bother you anyway. You do want to rename any labels that start with 1, 2, 3 or 4 (perhaps by putting the number at the end of the label name). No further action is required except consciously accepting to stop using the labels.