Locate the guide in your dictionary. You will typically find it toward the front of the book.
Glance at it for basic symbols, such as the identification of a short or long vowel sound. These symbols are used frequently and it will help you to understand them before looking anything up.
Keep a bookmark on the guide page so you can refer back to it as needed. Generally, symbols are listed at the beginning of the key, while letters are listed in alphabetical order. This makes it easier to find a symbol that you do not recognize.