Primary sources are:

• first hand accounts of an event
• materials created by participants or witnesses of the event(s) under study
• original records created at the time the historical events occurred
• raw data for the historian

Secondary sources are:

• works that discuss a subject, but which are written after the time that the event(s) occurred - [by someone other than an eyewitness]
• works that contain explanations/judgements/ discussions of past events
• works that explain or interpret primary sources

Primary Documents can contain older handwriting that can be challenging to read. Use these following guides to help you: 

Paleeography: Reading Old Handwriting from the National Archives

Useful Tips for Reading Handwritten Documents from State Records in New South Wales, Australia

Palaeography Help: from Leah Grandy at UNB

For a tutorial on basic cursive handwriting, see the following YouTube video.

Use keywords that describe your topic together with any/some of the following words:

Example: cold war and (letter* or narrative* or correspondence)
               and click on Search Everything

(* (asterisk) is the wildcard/truncation symbol in OneSearch, and would retrieve "letter" or "letters", etc.)

• Look at the publication dates of the book and the birth/death dates of the author:

• • The date of the original publication may give you an indication that you have a primary source. Look for the publication date or a note about the original publication.
    If the birth and death dates of the author are such that he/she lived during the time of your event you may have a primary source.

• Look at notes in the record:

• • There may be notes in the record which describe the material and give clues as to whether or not it is a primary source. For instance, if there is a note indicating that the work is a facsimile or a reprint, then you may have a primary source