In any given moment, our attention can be in one of three states: undirected, directed, or choicelessly aware.
Undirected attention is when we're not consciously trying to steer our attention in any specific direction, but it's moving seamlessly from fantasy about the future, to regret, to anxious thought, to happy thought, etc. Undirected attention is basically automatic associative thought patterns (e.g. yellow, banana, delicious, happy, monkeys, the jungle, interesting, movie about monkeys in the zoo, sad), and there's a brain network whose activity roughly corresponds to this kind of flowing process, called the Default Mode Network.
Directed attention, on the other hand, is when we're actively keeping our focus on something and not on other things. E.g. mixing milk and sugar into coffee, typing an email, folding origami (highly recommended brain activity), juggling, holding a yoga pose, meditating on your breath. Every second, our brains can be pulled in almost infinitely many directions, and in order not to, we have to engage our cognitive control, or focus. The brain network that gets activated in this state is called the Task Positive Network. When we do this, we are ignoring almost all of the input coming into our awareness, in favor of holding onto only a small chunk.
Finally, choiceless awareness is a combination of undirected and directed attention. It's a basic type of mindfulness, letting awareness flow from thought to feeling to observation to judgment to sensation back to thought, etc., all the while keeping our attention focused on the flowing motion itself, rather than on any specific stop along the way. It's not easy at first, and no matter how long you've practiced, there are still times when it's not easy because our lives and our minds are always changing. Sometimes we're feeling an intense emotion or just plain tired. That is also part of being human.
The first piece of good news is that we need strength in all three types of attention. The second is that practicing any type of meditation increases our capacity for both directed attention and choiceless awareness. To practice undirected attention, all we need is to get bored and do nothing (harder than it sounds).
Now the hard part (not as hard as most people think), actually practicing. More on that later. For now, I hope you enjoy using all three types of your truly amazing attention.