Control of the reactor in Unit #2 differs a bit from Unit #1 because it is more condensed in one place. The operator can either select 'group' control and then choose which rods he wants to move, or 'all' control, which moves all rods at once with the same switch. Movement speed depends on the number of rods selected. The fewer are selected, the quicker they can be moved. So, it is possible to move out single rod groups pretty quickly. This encourages you to play more realistically. In a real BWR, rods were pulled individually on opposite sides to build initial power. This is due to the fact that BWRs tend to be less stable at low powers (due to a lack of steam voids). Unit #2 is also less prone to rod imbalance, although high reactivity in a single group can still SCRAM it.
Automatic control can again be used for both rods or circulation control. However, when it comes to rods, you can choose to either pull all of them or only a selected group. This feature can be used, for example, for manual balancing, where selected rods can be adjusted manually, while autocontrol can move all of them to maintain the selected reactor power. Please be aware that both rods and circulation flow can reach their limits (at 0% or 100%) and, at that stage, cannot be controlled any more. You won't receive a warning about this.