how to set ovpn profile by radius server?

I’m using a freeradius server for ovpn Access Authentication, but I want that different aaa user in different subnet, because my server set different subnet have different privileges.

I set 2 profile in mikrotik, and add a user in /ppp Secrets, at here I can set Profile field, and it take effect.

BUT How Can I Set Profile IN FreeRADIUS Server? WHAT Attribute Can I USE?

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