Thomson aerosol aware mp=28 and real data for aerosols


It is not clear to me what kind of files I need to process into metgrid for real time aerosol (GEOS-5 product) into WRF with mp = 28.
Suppose that I want to run a forecast starting at 00Z for the 26th of June and a forecast length equal to 168 h.
I suspect that the aerosol file is somewhere here : GEOS-FP: Weather Analyses and Forecasts
On the portal, there are 2 buttons "Assimilation" and "Forecast". Which one is the right one ?
What is the filename syntax and how many files do I need to download : only 1 file at 00Z or several files at different times ?

Thanks a lot for any help,