You can decide how your incoming emails are organized by creating filter rules. The easiest way to do this is within an email that you'd like to reroute from your inbox to another folder. In the email, click the more actions icon and select "Create filter rule" from the dropdown menu. Enter a name for your rule and click "Add condition". You can choose to filter your email based on sent email address, subject, size, header, date and many others. Then click "Add action" to decide what you want to do with your email. You can file, copy or redirect it to another folder along with many other options. Then click "Save and apply rule now".
Tip: You can edit your filter rules at any time. Click the gear icon in the top right corner and select "All settings" from the dropdown menu. Next, click the arrow next to Mail in the menu on the left. Then click "Filter Rules". You'll find all of your filter rules listed here and you can edit them.