No need to ask more than once.

Are these contacts stored in a local mail client or online at Yahoo?  If the
former, examine the options of the client to see if it can export in a
format Outlook will import, like a CSV file.  If the latter, connect to
tyour Yahoo account, click Addresses, then click the Import/Export link at
the top right.  In the Export section, click the "Export Now" button next to
the words "Microsoft Outlook".  Follow the prompts.  Import the resulting
file into Outlook.