Unzipping media files / Install issues

I am new to Macs, so please bear with me

I downloaded The Unarchiver app to unzip zipped media files and now my mac is using the Unarchiver app to try and 'extract' every program I download. I can't install any programs because the Unarchiver can't extract anything from them. I understand how to choose a different program to run the install program, however I don't have another program with which to run the installation.

so, my question is twofold:

Is there another 'Winrar' type program which is mac compatible and will unzip zipped media files,

or

is there a program I can choose when trying to run an installation on a new program?

Thanks!

You've already posted this in another forum and your question was answered. Please do not crosspost. Thanks.