The way I have come to understand the 'soul' according to what ive read in the Bible is that we as humans are made of 3 parts. Body, Mind and Soul (Body 'physical body', Soul 'mind/logic/will/emotions, Spirit 'communication channel with God' are also used, but for this I am going with Body 'physical body', Soul 'communication channel' and Mind 'Will, emotions/logic/reasoning').
The mind is where we do our thinking, or logic and reasoning, which is also where we find our 'will', and emotions. The soul is the part that God communicates through. The body is the vehicle we need to move around.
When God puts something on our 'hearts' (soul), it can have influence over our mind. Which, makes the final decisions. This is why the Bible talks about planting seeds in our hearts (soul). The seed is planted in our soul, and then its up to the mind to make the final choice whether or not to water the seeds. It's like the soul is a garden for the Holy Spirit. He plants things in there, and it's up to you if you water those seeds. You can choose not to water the seeds, meaning that seed wont take root, or, you can water the seed, and that seed grows and turns into an action/physical response that over-rides the mind.
The Bible clearly states that the mind and the soul are always at war with each other. What the soul wants is always shot down by the mind (the mind that enjoys the carnal pleasures). Meaning, our logic, emotions, animal instincts/desires and reasoning usually always will go against what God wants. This is also why we are told in the Bible that we are to be 'Spirit lead', and not lead by our own minds (desires of the flesh). The Bible also says that through listening to the soul (and producing the fruits), the mind becomes renewed. We learn to put our faith and trust in our soul, (what God says), and in doing so, He reforms our mind. It's an actual process, and can be lifelong.
Im pretty sure I am missing some things, but that's sort of how I have come to understand it.