To convert OLM to PST manually, you can use the following steps:
Open Outlook for Mac.
Go to File > Export > Outlook Data File.
Select the folders that you want to export, and then click Next.
Browse to the location where you want to save the OLM file, and then click Save.
Open Outlook for Windows.
Go to File > Open & Export > Import/Export.
In the Import and Export Wizard, select Import from another program or file, and then click Next.
Select Outlook Data File (.pst), and then click Next.
Browse to the OLM file that you exported from Outlook for Mac, and then click Open.
Select the Options that you want, and then click Finish.
Greetings,
Peter