In the MoonBot terminal I placed a Buy order on a coin chart, then I bought it, and after that a Sell order was placed. Can I manually move it higher or lower?

Yes, you can left-click on a Sell order, hold it, move the Sell order up or down and then release it. The Sell order will be moved to the selected position. If you move the Sell order to the green order book this way, but the coin will be sold at the market. Alternatively, you can configure hotkeys in the Settings – Hotkeys tab for the quick move of Sell orders, use special combinations in the Settings – User Interface – “Mouse clicks settings for orders management” and right click an additional menu in the M (Use Multi orders) button where you can also configure combinations of manual Sell order moves.