Every trade begins as an instruction you send to the market: buy or sell. But behind that simple click is a full pipeline of routing, matching, and execution that decides the actual price you receive. Understanding this process is the difference between controlled trading and blind frustration. For a clear foundation on what trading really is beneath the interface, start with What Is Trading?.
All orders interact with two prices: the bid and the ask. The bid shows the highest price buyers are willing to pay; the ask shows the lowest price sellers are willing to accept. Your market order will always fill against these prices — not the last traded price you saw on the chart. To understand why fill prices look “off” or why entries feel more expensive than you expected, explore Bid vs Ask.
The difference between those two prices is the spread — a built-in toll for participating in the market. Thin liquidity, volatility spikes, or off-hours trading can cause spreads to widen, which increases the cost of entering or exiting a position. Many beginners mistake spread movement for “random price jumps,” when it's really the market adjusting to risk and activity. To see how spreads behave and why they matter for your execution quality, visit Understanding the Spread.
These mechanics — bid, ask, and spread — form the entire foundation of price movement itself. Every candle on a chart exists because orders walk through these layers, lifting or hitting liquidity as they go. If you want a complete walkthrough of how these forces build every tick and trend you see, read Basic Concepts of Price Movement.
Once you understand how orders interact with the market’s structure, trading feels far less mysterious. You can finally explain why your fill didn’t match the last price, why spreads hurt your entry, and why price responds sharply when liquidity dries up. Execution becomes a mechanic you can anticipate — not a surprise you hope turns out well.