giving customers options to change category before add to cart

[phemto]

i have a store for customizing phone cases 

i created a product attribute called phone model with values of iPhone, samsung, HTC, blackberry, Nokia 

and i also create a product attribute called samsung with values of Samsung galaxy s7,s6,s5,s4 etc

i want a situation when customers select a product they will have the ability to select any phone model they want 

for example if a customer select samsung i want a select option should display again listing all the values of Samsung product attribute e.g samsung galaxy s7,s6,s5,s4 etc and then add to cart; so on for iPhone, BlackBerry once they select the attribute a list of their respective attribute showing the list of their various values

 

or another way am looking at is if they select a case their should be a to select a category and a list of subcategory shows

e.g samsung s6,s5,s4,s3 is a sub category of samsung phone

iphone 4, iphone 5, iphone6, is a sub category of iphone 

 

so once they select the category their respective subcategories is displayed 

 

 

have been on this issue over a week now 

check my store website http;//slick.com.ng/store/65-brands