To get a link to Zotero you need to use {{zoteroSelectURI}} in the template, the resulting link will open an item in your Zotero library.
To directly open the file from Obsidian you need to edit the link substituting select with a direct open-pdf/library option
Below how the links should look like in markdown
[Show in library](zotero://select/items/1_4XK234ZW)
[Open PDF in default browser](zotero://open-pdf/library/items/FLQZ3X3K)