let customer choose product variant

New Member
1 0 0

Hello there,

                        Hey, guys, I need your help regarding Shopify product variant picking. in my Shopify store customer order product without choosing the right size of it and order what default select on the product. I want to add "pick an option" button on variant selector so the customer can not able to add to cart product without selecting the variant. I see some example there in Shopify community but i did not find the right code for the  theme (IMPULSE) please i really appreciate if you guys help  me out 

Thank you