Matrices are essentially a way to group similar items together by the attributes that they share. These similar items are referred to as "variants" and the attributes that they share are determined by their matrix attribute sets. Matrix attribute sets can have up to three attributes and Lightspeed Retail POS has three built-in matrix attribute sets:

• Color
• Size
• Color/Size

You can also create your own custom matrix attribute sets under Inventory > Matrix Attribute Sets.

To import items as matrix variants, you need to format them in specific way in your import file. To help you understand how to format matrix variants in your import file, let's pretend you're trying to import a plain t-shirt that comes in three colors (red, blue and yellow). To import each variation of the t-shirt as a matrix variant, you would need to enter the following in your import file for each variant:

1. Leave the Description column empty. Matrix variant names are created based on the Matrix Description + Attribute 1 + Attribute 2 + Attribute 3 columns.
2. In the Matrix Description, enter "Plain T-Shirt".
3. In the Matrix Attribute Set column, enter "Color". 
4. In the Attribute 1 column, enter the color of the variant (e.g. "Red").
5. Format the rest of the columns as you would for any item you're importing.

By doing so, you would create a matrix called "Plain T-Shirt" under Inventory > Matrix and each variant within the matrix would be called:

• Plain T-Shirt Red
• Plain T-Shirt Blue 
• Plain T-Shirt Yellow

Now, let's pretend you're trying to import a plain t-shirt that comes in three colors (red, blue and yellow), three sizes (small, medium and large) and 2 materials (cotton and tri-blend). Let's also pretend that you wanted to use a custom matrix attribute set for these t-shirts. To import each variation of the t-shirt as a matrix variant, you would first need to create the custom attribute set. You would call it "Color/Size/Material" and it would have three attributes (color, size and material). Then, you would need to enter the following in your import file for each variant:

1. Leave the Description column empty. Matrix variant names are created based on the Matrix Description + Attribute 1 + Attribute 2 + Attribute 3 columns.
2. In the Matrix Description, enter "Plain T-Shirt".
3. In the Matrix Attribute Set column, enter "Color/Size/Material". 
4. In the Attribute 1 column, enter the color of the variant (e.g. "Red").
5. In the Attribute 2 column, enter the size of the variant (e.g. "Small").
6. In the Attribute 3 column, enter the material of the variant (e.g. "Cotton").
7. Format the rest of the columns as you would for any item you're importing.

By doing so, you would create a matrix called "Plain T-Shirt" under Inventory > Matrix and each variant within the matrix would be called:

• Plain T-Shirt Red Small Cotton
• Plain T-Shirt Red Small Tri-Blend
• Plain T-Shirt Red Medium Cotton
• Plain T-Shirt Red Medium Tri-Blend
• Plain T-Shirt Red Large Cotton
• Plain T-Shirt Red Large Tri-Blend
• Plain T-Shirt Blue Small Cotton
• Plain T-Shirt Blue Small Tri-Blend
• Plain T-Shirt Blue Medium Cotton
• Plain T-Shirt Blue Medium Tri-Blend
• Plain T-Shirt Blue Large Cotton
• Plain T-Shirt Blue Large Tri-Blend
• Plain T-Shirt Yellow Small Cotton
• Plain T-Shirt Yellow Small Tri-Blend
• Plain T-Shirt Yellow Medium Cotton
• Plain T-Shirt Yellow Medium Tri-Blend
• Plain T-Shirt Yellow Large Cotton
• Plain T-Shirt Yellow Large Tri-Blend