Set a discount voucher using user groups

[m3s]

I want to know if is possible to set up a voucher with a specific price as a discount for every user that signs in as a customer.

Eg. A voucher for a discount of 20 euros for buying products of all categories that have a minimum cost of 60 euros (if less the customer cannot use the voucher).

I tried to set up the rule in groups session but it allows me to set a discount persentage only.

 

ps. I am new to prestashop and also to prestashop forum. Please if this change is very simple just let me know at least where I have to look to set it up.

 

Thank you in advance.