What is the name of the domain?
newskin.ua
What is the issue you’re encountering
Hi. I have ordered Cache Reserve but don’t have any data stored in it for the last 2 days. Should I create a Cache Rules or should it work by default without any rules?
May I ask if you’ve tried to Purge Everything in the meantime, so Cloudflare would catch and cache things “newely” just in case and put in the Reserve? 
From the Docs there are some requirements for the resources to be cached as reserve and limits:
I do see the HTTP cache headers being present, with HIT status therefore, have age and priority as well.
May I ask have you got any configured already for some specific need?
In short, yes.
Navigate to the Cache Rules and create a rule Eligible for Cache Reserve. Modify the parameters, TTL like 12 hours, add newskin.ua as a hostname and set the Minimum filesize as well.
How much website traffic daily you’ve got?