From the Leidseplein you walk into the Leidsestraat, On the right side you'll find a McDonald's restaurant on the corner.
There you walk into the Lange Leidsedwarsstraat.
After 80 metres you'll find Puri Mas on the left side of the street on the first floor.

Public transportation
The Leidseplein can be reached by taking trams 1, 2, 5, 7 or 10 from Central Station.