Once you've got the RAR App set up, you can start opening rar files. Open the RAR App. Find the rar file you want to open in your files. Tap the file to open it, entering its password if there is one.

The files will appear in the same directory as the original Zip, so just tap one to open and examine the contents. The three dots to the side of each file will let you share, rename, delete and ...