FreeTDS conf? How to use it?

Hello there, I am curious about the freetds.conf file inside /etc/freetds.conf once inside the devilbox shell.
As far as I understand it should be used to connect to MSSQL dbs, but it seems that the driver is not installed, am I right?
I already installed sqlsrv driver as stated in the guide, but I do not understand the role of that freetds configuration file, and how could I leverage on that to connect instead of sqlsrv.