You can move your sketches by selecting them and using the arrows to reposition them.
Although you can select each line or arc of a sketch, you can select the entire complex sketch by double-clicking or long-clicking with your mouse or trackpad a part of your sketch. Optionally, you can select the entire sketch plane from the Items manager.
Then, you can use the arrows to move the sketch anywhere on the grid.
You can even copy and move the sketch.