Sila means ethics, or morality. There are many Suttas that describe how Sila is practiced. The most basic way for a layperson to practice Sila is to keep the five precepts.
- Panatipata veramani sikkhapadam samadiyami
I undertake the precept to refrain from destroying living creatures.
- Adinnadana veramani sikkhapadam samadiyami
I undertake the precept to refrain from taking that which is not given.
- Kamesu micchacara veramani sikkhapadam samadiyami
I undertake the precept to refrain from sexual misconduct.
- Musavada veramani sikkhapadam samadiyami
I undertake the precept to refrain from incorrect speech.
- Suramerayamajja pamadatthana veramani sikkhapadam samadiyami
I undertake the precept to refrain from intoxicating drinks and drugs which lead to carelessness.
(http://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html)
After that there are the eight precepts, the ten precepts, and the monastic precepts.
One thing to bear in mind however is that these precepts shouldn't be looked on as just being rules given to us to follow. We should look on them not as restrictions put on us by our religion, but as greatly beneficial spiritual practices we take on because they benefit both ourselves and others.
Also it is important to remember that the five precepts are only a basic summary of morality. Just because something isn't technically covered by the precepts doesn't mean that it is totally ok to do. One should always consider the effects of ones actions on one's self and on others.
One of the most practical Suttas giving a description of how to discern right from wrong is the very famous Instructions to Rahula at Mango Stone. It explains how one should contemplate and reflect on one's actions and character in order to develop Sila.
(http://www.accesstoinsight.org/tipitaka/mn/mn.061.than.html)