In APA format, you follow the author-date method of in-text citation, or citing a source within the text of your paper, in addition to the reference list at the end of the paper.

This means that the author's last name and the year of publication for the source should appear in the text, like, for example, (Jones, 1998). One complete reference for each source should appear in the reference list at the end of the paper, in addition to the in-text citation. 

Additional key attributes of APA In-Text citations:

• If you are referencing an idea or concept from another source, but NOT directly quoting the material, or making reference to an entire book, article or other work, you only have to reference the author and year of publication and not the page number in your in-text reference. This also applies if the source doesn't have page numbers, like a web source. 
• If you are directly quoting or borrowing from another work, you should include the page number at the end of the citation in parentheses.
• In in-text citations, use the abbreviation “p.” (for one page) or “pp.” (for multiple pages) before listing the page number(s). Use an en dash for page ranges. For example, you might write (Jones, 1998, p. 199) or (Jones, 1998, pp. 199–201). 
• Regardless of how they are referenced, all sources that are cited in the text must appear in the reference list at the end of the paper.
• If referencing the same item multiple times in a paper, you should still include those in-text citations.

If you would prefer to go through a tutorial on how to use APA Citations, check out this tool from APA:

• Academic Writer Tutorial: Basics of Seventh Edition APA Style
• Try out this worksheet from the Writing Center.