Hi there @Hiroyuki_Todoro!
Don here from Shopify. :)
You can check out their help centre here, find specific documentation for the Testament theme here or you can reach out to them directly by clicking on the 'contact' link in the top right of the store.
They will be able to field any queries you have about the use of their theme and will provide support as appropriate.
How are things going for your store otherwise?
|an hour ago|
|2 hours ago|