Please unpack the whole package after downloading it from Themeforest.
On that extracted themeforest-boom-shopify-theme,You can find files like 

Documentation
boom-other-demos
boom-fashion-demos
boom-main-demo.zip 
Log.txt
Readme.txt.


You need to install the file "boom-main-demo.zip" for the primary boom demo.

If you want other demos, just pick from the boom-other-demos folder.

Online documentation link: 
https://themessupport.com/dt-shop/boom/
 

Kindly refer our documentation for installing the theme and doing customization. 
If you need any assistance, plz contact us through support@wedesignthemes.com


Thankyou,
Designthemes.



