As you see I’ve highlighted “Local Folders”, right click in “Folders” menu and choose “New folder”, you will now get this window.
Name your folder (I used “Techsupp247”, choose whatever you like), choose where it should be located and press “OK”. If things are done right, you should now have a new subfolder under “Local folders”. You can also choose to make a new folder during the setup of making a filter, but I found it more easy to make the folder first.
To setup a filter in Thunderbird, go to Tools, and click “Message Filters”. The “Message Filters” window will pop up. Click New, and the Filter Rules dialog will open.
Make sure you type a descriptive Filter Name that you’ll remember in six month – “TechSupp247” is not ideal, for example.
The best way is to explore a bit on your own for what settings you want. I made a filter which filters mail with comes to the mail address “firstname.lastname@example.org”, and place them in the folder “TechSupp247 and labels it as Important (gives it a bright, easy to spot color). When you are done, press “OK”, and you’ll get this window: