One of the biggest problems with Gmail is that too many users become bogged down with thousands of emails in their inbox.
Because the system doesn’t use folders, the messages don’t disappear away from view. Instead, you need to archive your mail.
Archiving keeps all your messages in the system, allows you to search them, but takes them out of your inbox. Make sure to archive all the messages you want to keep. You can even select all messages, and then click the “archive” button at the top to do it all at once.