"..not sure what freedom from religion means !"

Well Pete, it is the logical position that is implied when the phrase "freedom OF religion" is used. If everyone is implicitly granted the right to worship as they please, this must be understood to mean that everyone's beliefs are personal and independent.
"Freedom OF religion" must not be interpreted to mean that someone must have a religion... especially not some specific religion. Thus, the phrase perhaps should be "freedom of thought and the consequent freedom to practice certain thoughts & beliefs.... as long as they do not infringe on the rights of others".

My characterization of this would be: 'If we all woke up one day to find 99.9999% of all humans were NON-religious, and there were, say, only 127 Christians left, those 127 should not be restricted in their beliefs.' 'Likewise, if there were 99.9999% Christians, the 127 non-believers should also be respected and tolerated'. (I ignore the various other possibilities to shorten the point.)

In reality, I suspect that humans being what they are, neither ideal situation would prevail. I especially doubt that billions of Christians would tolerate 127 atheists/non-believers.

In the USA, our Constitution formally recognizes this point (no restrictions ON religious practice and no requirement FOR religious practice).... but many are, even today. working to get certain forms of (mostly fundamentalist Protestant) religion accepted as the norm and semi-official.
So- "freedom FROM religion" is a position- not a religion in and of itself.