Please make sure that you have unzipped the theme package that you download on Theme Forest before upload it to your store. Otherwise, you will get the issue: zip does not contain a valid theme: missing template "layout/theme.liquid". Then please upload Kalles_2.x.zip file to your store.
Notice: With each DATA_JSON file contains demo files, please check all of them if you want to find any demo.
Notice: You must install Sublime Text (or other editor softwares) to your device in order to open index.json and settingdata.json. You can click here and choose the suitable Sublime Text version to install.
Please note that the Kalles version on EComposer is separate from the Kalles Shopify theme.