Basics of Dow theory

The market has three trends
Primary trend is the major trend for the market. It indicates how the market moves in the long-term. A primary trend could span many years.

Secondary trends are considered to be corrections to a primary trend. This is like an opposite movement to the primary trend.

Minor trends are fluctuations to the market movement on a daily basis. These trends last for less than three weeks and go against the movement of the secondary trend.

Trends are confirmed by volume
The trend in the market should be supported by trading volumes.

Buy Order can be placed after high bottom and high top is formed.

Sell order should be placed after Low top Low Bottom is formed.

Line Chart should be used for Dow theory.
Minimum look up period is 2 years.

Support is something that prevents the price from falling further. The support level is a price point on the chart where the trader expects maximum demand (in terms of buying) coming into the stock/index. Whenever the price falls to the support line, it is likely to bounce back. The support level is always below the current market price.

Resistance is something which stops the price from rising further. The resistance level is a price point on the chart where traders expect maximum supply (in terms of selling) for the stock/index. The resistance level is always above the current market price.