The AMA citationstyle is not one of the default citations styles in Zotero. You will need to add that style manually. Here are the steps:
In the Standalone version of Zotero, open the Edit menu.
Select Preferences in the drop down menu.
Select the Cite tab in the Preferences bar.
Click on the "get additional styles" link.
Search for 'American Medical Association' and select "American Medical Association (no URL)"
The citation style should be added to your Style Manager. Click 'OK' to confirm your addition.
You can also visit the Zotero Style Repository webpage in Firefox or Chrome with the Zotero Connector plugin installed to install styles directly into Zotero.
Open a browser for which you have installed the Zotero Connector.
Browse to a website that represents an item you wish to add to your Zotero library as a reference. This item may be a website, book catalog record, article record in a database, video, or more.
You should see an icon appear in the address bar or in your plug-ins that corresponds, more or less, to the type of item represented by the website (e.g. book, document, etc.). Click this "Save to Zotero" icon to create a new item record based on the metadata in the exposed page.
If the Zotero Connector is grayed out, you can force Zotero to save a Web Page item instead by right-clicking (click-and-hold in Safari) on the Zotero save button and choosing “Save to Zotero (Web Page with/without Snapshot)”
Open your Zotero library if it is not already open and confirm the creation of a new item. You may now manually edit any of the information automatically collected from the webpage, including the original item type by clicking in the appropriate field.
Open your Zotero Library in the Standalone tool or official website (zotero.org).
Locate the "add" icon (encircled plus sign) within the Zotero interface.
Select the type of item you wish to add (e.g. book, book section, document, journal article, etc.) from the dropdown menu (in the web version) or click 'more' in the Standalone version to select from a wider selection.
Begin to fill in data manually for the item record that appears by clicking on each metadata field. You can enter basic data (e.g. title, author, publisher), as well as notes, tags, and files from your computer.
Recommended: when done, click the "sync" icon (green circular arrow) to bring your remote Zotero library up to date.
Describes the various ways to add items (e.g., books, journal articles, web pages, etc.) as items in Zotero. Also includes directions to archive online pages that are not automatically recognized by the Zotero Connector.
