Changes to simple GUI in Visual Studio

We want to use the following C# tool which provides a simple GUI to OpenSSL:
https://github.com/deviousasti/openssl-wizard

The following changes are required:

1) Home tab:
a) Delete "Get Version" button

2) Combine tab:
a) Add field CA Cert

b) Change the textbox fields Certificate, CA Certificate, Key and PFX Certificate to a file dialog -> the variable shall be the complete file path with commas, i.e.: "c:\path\to\file.crt"

c) Validate filepaths - throw error message if file is not readable (Certificate, CA Certificate, Key) or not writable (PFX Certificate) or fields left empty

d) Validate PFX Passphrase field - throw error message if field is empty