1a) Extract the siavpos.ocmod.zip and upload the files from the upload
directory to their corresponding location on the server with ftp/ssh.
1b) Or use the extension installer, click the Upload button and select the siavpos.ocmod.zip package.
2. Overwrite files/folders as necessary (no core opencart files will be overwritten)
3. Login to the Open Cart admin section and go to Extensions > Payments
4. Find Sia Virtual POS in the list of extensions
5. Click "Install" and then "Edit" the payment module settings
Note: Enable the PHP OpenSSL extension in case it is disabled and when 3DSecure V2 is used.