Turn on the radio ... Watch TV ... Read a newspaper or magazine.
Advertising is all around you.
If you don't understand it by now, I'm not even gonna try to explain it.
What advertising method is used buy retailers to increase the number of shoppers in the store and how do I understand it?
If it is still just a small retail store, I don't see the need for the for tv or radio advertisement since it is very costly. But I think having promotional discounts will help printed in a tarpaulin posted outside your store as well as posting it in social media.
There are tons of methods and it will be really difficult even to mention them all. Various finance affiliate programs, sales, digital marketing, tricky placement of products on the shelves, bright and memorable ads. And it's only the beginning.