If you're trying to install ProcessWire on a Synology NAS using the WebStation service, please refer to notes below.
I've created this mainly for web searches.
I'm going to assume that you're at the installation screen and the first issue you'll have is trying to connect to a database. There's 2 things here you need to note
MariaDB is running on Port 3307. You're probably used to running on port 3306 and this might even be what the installation screen pre-populates
The Host field must be set to localhost:3307 and not just localhost