How does the GC Wizard decrypt or encrypt with the Hill cipher?

Decrypt

After entering the text, key, alphabet and matrix size, and any fill characters, the text is decoded and output directly.

The matrix and the coding of the alphabet are also output.

Encrypt

After entering the text, key, alphabet and matrix size, and any fill characters, the text is decoded and output directly.

The matrix and the coding of the alphabet are also output.