Download the latest version of 7zip from this link.
The latest version is present on the top table. Select the one based on your operating system for example Windows or iOS.
Install 7zip and use it to unpack the rar or zip files.
After installing 7zip, right-click on the rar or zip file and select 7zip and then select Extract Files from the menu.
Select the destination of the extracted file and click OK.
The files will be extracted in the location specified.