build a shopify theme

I want you to design a custom theme but not to shopify, But to a very similar website calles "salla", I don't know if the process will be the same, but here is their website https://docs.salla.dev/docs/twilight-themes-documentation/44069a6e14851-meet-the-twilight , just to clarify, I wan't to upload it on salla themes store, thank you