How to Load historical data in MetaTrader
How to Get the minimum needed number of bars, that your indicators require to be calculated.
How to Export data directly from the chart
How to Check charts settings for bar number.
Navigating the MetaTrader chart so you can find out more about your data
How to Use shorter periods of data to make better calculated backtest, to avoid ambiguous bars
Where/How to find the MetaTrader historical files