Alphabet

Please look at the link to underastand my Request better.( For an example: https://www.theoutnet.com/en-DK/Shop/Designers)
First i click on menu Designer , it takes me to the page where u can find the alphabet A-Z. If i click on A, it takes me to a page where all the products , which names start with the alphabet A. Then , If click on one product in A column , for example , the brand name Agnona—it SHOWS the whole list of Agnona products ..

Can you please tell me how I can do the same