easy job you will need cerium oxide if they are light Scratches, if they can be felt with a fingernail they will need to be ground out with a stone first < i would not do this if you have never done it
you will want
some cerium oxide powder for the polishing
a polishing pad (suggest lambs wool, felt or leather) mounted on a backing disc
low speed drill (1500 rpm or less) to use with the polishing pad - polishing too fast will generate excessive heat and may crack the glass.
a marking crayon to mark the inside of the glass (use this to guide you when polishing)a cleaning cloth to wipe and allow inspection of the work area
small spray bottle - use to apply mixture to glass and keep moist while polishing
how to do it
Mix some polish into water to a form a thin slurry (eg. milk-like consistency) - we suggest mixing in a small spray bottle which can be used to apply to polishing pad
Clean glass thoroughly to remove all traces of dirt and grease
Apply polish mixture to the polishing pad
Mark the inside of the glass with the crayon to identify the area to be worked
Mount pad in the drill and apply to work area.
Move pad up and down, left and right in work area.
Keep the surface wet to prevent glass getting hot - if sufficient polish has already been applied, then just spray a fine mist of water to keep the area cool.
Wipe off residue and inspect repair - keep working until polish is satisfactory
Wash and store pad for later use