The free agents will have an owner of "Free Agent". They will be listed on the transfer list just like any other player whose owner is selling them.
To have a salary that qualifies for listing as a free agent, they will probably have major skills (shooting, rebounding, defense) in the proficient+ range.
For example, If you search the TL for players with IS above proficient, a little over 10% of them are free agents. The deadlines will be on Wednesday and Thursdays.