help me understand this hadith

'Reported by Sahl bin Sad (RA): The Prophet (peace be upon him) said, 'Verily! 70,000 or 700,000 of my followers will enter Paradise altogether; so that the first and the last amongst them will enter at the same time, and their faces will be glittering like the bright full moon.' (Bukhari)

i dont understand this hadith. please help me understand.