syncing an outlook account with gmail

I would like (on the client side, say through Outlook) to periodically take new messages from my outlook account and upload them to my gmail account (but not the other way around).

What is the way to do it? I noticed there is something called GWMMO, but it is only for Windows, and I use a mac. I couldn’t find any further information.

This needs to be done, again, on the local client side, so I can’t set on outlook.com, for example, to forward emails to my gmail account.