Step 1: Log into your NAS as administrator and go to Main Menu → Package Center → Settings and set Trust Level to Synology Inc. and trusted publishers.
10 Source packages. The installation using the ownCloud zip or tarball is the most common option and is best for production environments. Release Notes · Docs & Guides · Older Versions · Changelog
I did for years and switched to Synology Drive, which is clearly more stable, much easier to maintain, and have less sync issues (none in fact). No regrets.