Horizontal Support and Resistance

I'll try to explained it this way
Support : level above current price
Resistace  : level below current price

Let see some example:
This is AUDUSD weekly chart (August 2015). To make it easy, i removed all indicator

The yellow doted line is a resistance level (how to draw support and resistance). The level have been touch four times. For the 5th time, the market break it out and continue lower.
So resistance level is a level that prevent the market to going down. This mean the price is likely to "bounce".

To trade support and resistance level, you must learn about candle stick pattern and price pattern to confirm the price action around the level.

Enjoy your trade.