Need help with Variants

When I try to add a variant to a specific product, to give option to buy 2 for 35.00 or 1 for 20.00, the variant choice is not accepted. I need to know how to word it. I use website builder. I'm sure I'm just not entering the right info in the variant sections. I can't find an answer as to how to fill it out if I am wanting to offer a different price if someone wants 2 for the discounted price. I tried to create something in the discount section, but instead of just adding it to the specific item, it made the discount apply to all items. So, I deleted that discount section and went back to trying to add a variant. I hope this isn't confusing. I really need someone to help me with this problem. I tried looking it up on Google but didn't find an answer.