How do I make a discount "to" a value and not "of" a value

[Lemon_Tree_Cafe]

Hi,

I'm making a shopify website for my cafe and I haven't learnt any coding at all.

I'm trying to make a deal/discount called "Pastry and Coffee Deal", where customers buy a product and a coffee then pay a value of 5.50 euros.

However, with discount codes the settings are making a discount that deducts a certain value.

Can anyone help me with this?