To import MBOX files into Outlook manually, first, open Mozilla Thunderbird or another email client that supports MBOX format. Import your MBOX files into the client using its import feature. Next, drag and drop the emails from Thunderbird into a local folder. Afterward, use a tool like the BLR MBOX Converter Tool to convert the local folder into a PST file. This PST file can then be easily imported into Outlook. The BLR tool simplifies the process, ensuring a smooth and accurate conversion, and allows you to migrate your emails with minimal hassle.