The Location of the Preferences box varies between PCs and Macs.  See images below.

PC:

MAC:

• Link and sync your Zotero library with your zotero.org account:

• Username should be pre-filled with the name you used when creating Zotero account.​

• Very Important: Make sure “Sync automatically” box is checked

• Zotero's current free storage limit is 300 MB.  PDF attachments use a lot of MBs, so you may want to consider un-checking "Automatically attach associated PDFs and other files when saving items."  Click for more ideas on conserving (or expanding) storage space.

• Consider un-checking "Automatically tag items with keywords and subject headings." Leaving this checked will allow Zotero to import supplementary metadata it detects. This level of metadata does not always import cleanly and may interfere with a tagging system you may wish to create.

Styles tab: Choose desired citation style. You may change this at any time.

Word Processors tab: Check for Word plugin installation.

Consider which "Add Citation" dialog box you would like to use.  See images of both default and "classic" below.

• Default: Begin typing in title or author of what you'd like to cite and select the item you need.

• Classic: Allows you to "drill down" from folder to item. This view also prompts you for a page number.