Hello and Welcome.
If you want to use files from inside a .7z file, you need to have installed 7zip on your windows. You can download it very fast and easy from here and then follow the tutorial.
Go to folder where 7z file is located on your computer or laptop and keep right mouse button pressed for 1 second and release the finger, then select 7-zip and Extract Here.
A folder will be created in moment when press Extract.
Enter in that folder and there is desired content from 7z file !
Simple enough ? oh no ?
Look at this photo Example :
We expect to visit us in the future if you have any problems !