The present indicative is almost always the first verb form you will learn when studying Spanish. It is used to talk about current actions. In the case of leer, the present indicative is used to refer to the act of reading when that act is presently going on.  Example: "She is reading the novel," Ella lee la novela.  yo: leo  tú: lees él/ella/usted: lee nosotros/-as: leemos vosotros/-as: leéis ellos/ellas/ustedes: leen Use the preterit indicative to refer to the act of reading when that act has concretely happened in the past and has since come to a clear end and is no longer being performed.  The verb leer is irregular in the preterit indicative. Example: "I read that novel last month," Lei esa novela el mes pasado.  yo: leí tú: leíste él/ella/usted: leyó nosotros/-as: leímos vosotros/-as: leísteis ellos/ellas/ustedes: leyeron The conditional indicative is used to describe an act of reading that would be done at some point in the future as long as another condition or circumstance ends up being true.  Example: "In that case, Pablo would read Hemingway's novel," En ese caso, Pablo leería la novela de Hemingway.  yo: leería tú: leerías él/ella/usted: leería nosotros/-as: leeríamos vosotros/-as: leeríais ellos/ellas/ustedes: leerían

Summary:
Use the present indicative. Conjugate leer in the preterit indicative. Switch to the conditional indicative.