After downloading Kalles from Theme Forest to your device, please make sure that you have unzipped the theme package before uploading it to your store. Otherwise, you will get the issue “zip does not contain a valid theme: missing template “layout/theme.liquid“. 
When you install Kalles successfully, let follow these stages to import a Demo theme.
Please keep in mind that the Import Demo ONLY allows you to import layouts and settings for the homepage. You CANNOT import content like images, blogs, and so on.You also have to configure yourself on other pages, such as products, collections, etc.
1. With Kalles 3,00
Step 1: Open folder “Kalles 3.00”
After downloading, open file “Kalles 3.00 (Support OS 2.0)”. 
Step 2: Open “Kalles 3 data”
You can see two files, click on “Kalles 3 data” to continue. 
Step 3: Edit theme and copy data file
Choose a Home Demo that you want. Here are some of Home Demo: 
After clicking on a Home Demo that you like, you will see two files index.json and settingdata.json.
Notice: You must install Sublime Text (or other editor softwares) to your device in order to open index.json and settingdata.json. You can lick here and choose the suitable Sublime Text version to install.
Step 4: Copy code to the theme file
- Open Edit Code on Shopify: Then, go back to Shopify, from current theme (Kalles 3.00), hover on Action and choose Edit Code.
- Copy Index.jon and Settingdata.json codes
In order to import a Demo, you must copy both Index.jon and Settingdata.json codes.
- Click on finding tool and type “index”. When {/}index.json appears, click on it. You will see code values, then, you press Ctrl+A>>Delete.
- Open Sublime Text and drag file index.json (that you’ve downloaded) into Sublime Text >> Ctrl+A >>Ctrl+C to copy all code values.
- Go back to Shopify edit code page, press Ctrl+V to paste all the code values.
- Click on Save and you have completed to import a Demo.
Let see an example: 
To copy settingdata.json code, you can do the same steps with index.json.
After importing both Index.jon and Settingdata.json codes. You have already completed Import a Demo Page.
2. With Kalles 2.7.4 and earlier
Step 1: Open data config file
- On the file downloaded fromhttps://themeforest.net/, it has a file called ‘DEMO DATA’.
Then click on “Kalles 2.7.4”. You will see two files like that. 
- You need to go DEMO DATA >> Choose the Home layout you want >> Open file >> Copy all data
Notice: You can use the Sublime Text to open the file.
Then you can see: 
Step 2: Copy to your theme
- Go to Customize >> Theme actions >> Edit code
- Open “setting_data.json” file >> Paste all the data which copied from ”DEMO DATA‘ to here >> click to ‘SAVE‘
You should watch this tutorial video to know more: https://www.youtube.com/watch?v=sUDh0V_HMMs&list=PLZSqbv2i8LOBCosw-vNCjyhmJ5BmrmCqA&index=2