After registering for a free account, you can log in to access your personal library on the Zotero website. If you also use the Zotero app on your computer, be sure to set up syncing so that changes you make online are reflected in the app, and vice versa.
Direct Import: Click "Enable Syncing to Online Library" in the "Is Zotero Running?" pop-up window.
Edit an item: click on the item, then click the "edit" icon
Add attachments such as PDFs: Click on the item, then drag it to the bottom of the page; click [Upload Attachment]
Create bibliographies: click on the item, click the "cite" icon in the left corner, and then select the citation style you want; you can also create a group of citations at once by checking every item you want.
Add tags and notes: click on the “Edit’ icon, go to the bottom of the page
and click on the “plus” button, and then click on the “Add notes” button.
Organize your folders: To move an item or several items into or out of a collection, check the box to the left of it and then click the "add to folder," the "Minus folder," or the "Trash can" icon located above the item(s).