How to set up two stores for different markets under one domain and subdomain?

Hi, the title desribes the problem.
Due to limitation of Shopify payments for Polish market we were advised to open second store in Shopify - one for polish currency ( PLN) and second for EUR. We did so, we set up subdomain on our external domain provider account, set up all server requirements.
Now - how two set up these shops for different markets and currences?

Please help! Im struggling with no info, no manuals, no reasonable help - even online help ( Pakistan, India, Bangladesh?) have no idea what to do, because they do not understand that there are no Shopify Payments in Poland.

I am interested in this topic as well. :slightly_smiling_face: I see no one else is looking for the answer. What did you do finally?