How we can use the function prctile?

The goal is to seperate the value of "montant depot" into quintiles I can't understand this code taille=1*(montant_depot<=prctile(montant_depot,20))+... 2*(montant_depot>prctile(montant_depot,20) & montant_depot<=prctile(montant_depot,40))+... 3*(montant_depot>prctile(montant_depot,40) & montant_depot<=prctile(montant_depot,60))+... 4*(montant_depot>prctile(montant_depot,60) & montant_depot<=prctile(montant_depot,80))+... 5*(montant_depot>prctile(montant_depot,80)); up_taille=grpstats(underpricing,taille,'mean');

I use this one instead the other Sep_centile = prctile(montant depot,[20,20,20,20,20])