See your trading activity visualized on a price chart as a small dot, colored corresponding to your up-and-down candle colors.
You can toggle whether you see your past trades and open orders as circles overlaid on that market's price chart. To change this setting, click the cog wheel in the upper right and select or deselect "My Trades" and "My Orders".
Past trades and open orders will only show on charts for exchanges where trading is supported (those in the top section here).
Toggling past trades and open orders on your chart