The core difference
Both are "pending" orders — instructions to buy later, only if the price reaches a level you set. The difference is which side of the current price that level sits on. A buy limit is placed below the current price ("buy it if it drops to here"). A buy stop is placed above the current price ("buy it if it rises to here").
The simple memory aid: a limit waits for a better price, a stop waits for confirmation that the price is already moving your way. They suit opposite ideas about what the market will do next.
When each one is used
A buy limit suits a trader who thinks the price will dip to a support level and then bounce upward — they want to buy the dip at a cheaper price. A buy stop suits a trader who wants to buy only if the price breaks upward through a level, confirming momentum before committing.
Neither is better; they express different plans. Using the wrong one for your idea is a classic beginner slip that puts your entry on the wrong side of the price.
The numbered steps in MetaTrader
Step 1: Double-click the instrument in Market Watch to open the "Order" window.
Step 2: Change the "Type" dropdown from "Market Execution" to "Pending Order".
Step 3: In the pending-order "Type" field, choose "Buy Limit" if your price is below the current market, or "Buy Stop" if it is above. The platform will reject the wrong choice for the side you picked.
Step 4: Enter the trigger price in the "at price" field, set your Volume small, and optionally add a Stop Loss and Take Profit.
Step 5: Click "Place" to submit. The pending order appears on your chart as a dashed line and in the Trade tab, waiting; it becomes a live trade only if the price reaches your level.
Managing a pending order
A pending order that never gets reached simply sits there doing nothing until it expires or you delete it. To remove or change one, right-click it in the Trade tab and choose "Modify or Delete Order". You can also drag its line on the chart to a new price.
It is easy to forget about pending orders you left in place days ago. Review them regularly, because a stale order can suddenly fire on old logic when the market finally reaches it.
An honest risk note
A pending order can fill during fast news at a worse price than the level you set (slippage), and a buy stop in particular often triggers right as a breakout fails. Always attach a stop-loss to a pending order so a bad fill still has a defined limit.