What the Strategy Tester does
The Strategy Tester runs an automated strategy (an "expert advisor", or EA) against past price data to see how it would have performed. It is built into MetaTrader and is the fastest way to get a rough sense of whether a rule-based idea has any merit before risking money.
Backtesting is genuinely useful, but it is also one of the easiest tools in trading to fool yourself with. Learning to read the results honestly matters as much as running them.
The numbered steps
Step 1: Open the Strategy Tester (View → Strategy Tester, or Ctrl+R). A panel appears at the bottom of the platform.
Step 2: Choose the expert advisor you want to test, then the symbol (instrument) and the timeframe.
Step 3: Set the date range for the test and, importantly, the modelling quality or tick source — poor-quality historical data produces misleading results.
Step 4: Set the starting deposit and any inputs the EA exposes, then click "Start". The tester replays history and simulates every trade.
Step 5: When it finishes, open the "Results", "Graph", and "Report" tabs to see the simulated equity curve, number of trades, and summary statistics.
Reading the results without kidding yourself
Look beyond the final profit. Check how deep the worst drawdown was (the biggest peak-to-trough drop), how many trades there were (a handful proves nothing), and how smooth or lucky the equity curve looks. A strategy that only made money because of two enormous trades is fragile.
Be deeply suspicious of a backtest that "optimised" dozens of settings to fit the past perfectly. That is called curve-fitting, and it almost always falls apart on new data. A result that looks too good usually is.
An honest risk note
A backtest shows what a strategy would have done, using historical data, ideal fills, and hindsight — none of which match live trading, where spreads widen, orders slip, and conditions change. Good past results are not a promise of future ones, and many strategies that shine in the tester lose money live. Always forward-test on a demo account before ever considering real money, and treat the tester as a filter for bad ideas rather than proof of good ones.