Try using the vMail OLM to PST Converter if you don’t know how to convert OLM to PST manually. Because third-party tools are thoroughly tested program, whereas the manual way is not ideal for all users.
One of the most precise program for transferring data from Mac Outlook to Windows Outlook is vMail OLM Converter. You can also utilize software to import your Mac Outlook mailbox to PST if you have a huge inbox. You should not worry because the software works with every version of Windows and Outlook. You can move mailboxes to Office 365 using a variety of export formats, including EML, MSG, Live Exchange, etc.
Know more info- https://www.vsoftware.org/olm-to-pst-converter.html