A Lock is several positions open for one instrument in different directions on one trading account. We shall discuss it on the example of Forex, as long as on stock markets, in the USA specifically, locking one instrument is illegal; one can only hedge risks by other instruments (buy one, sell another). Locking is also possible with CFDs.
Strategies section covers a lot of data on the latest trading strategies on Forex. Here you will find strategy descriptions and possible scenarios to open/close positions.
The classic Pin Bar forms on the critical support/resistance levels at the maximal/minimal values in the places where, theoretically, the trend may end. However, there are more options for the Pin Bar formation, which are the places of the trend correction.