If at equilibrium there is no more change in gibb's free energy, then why in the equation
ΔG = ΔG° + RT ln Q
we take delta G to be zero and delta G0 not zero but a value? If there is no more change in gibb's free energy then why is it that we don't take every G as zero?

Could you explain this or link me to a site which explains thermodynamics from a to z because I am getting confused

What I mean is, if the system is a equilibrium delta G and delta G 0 should be zero