There are some common platitudes heard in Christian gatherings. When you are dealing with some kind of struggle that is weighing you down, invariably someone will utter, "Just give it to God." I have never understood fully what this means. Sometimes folks who have no answers or sage advice to dispense, feel they have to say something that at least sounds good. However, despite my lack of understanding of "giving it to God", I do think there is a kernel of relevance in this statement, namely, that we should live in constant communication with our God. When we labor and flail and sink under our own efforts, when we are so tired and frustrated and spent that we have no strength to pray, there is someone who indwells us that pleads and groans to God on our behalf. This someone is the Holy Spirit.
I think the notion of God, His Son, and His Spirit being three distinct entities but only one being, if you try to wrap your mind around it, might actually cause your eyes to bleed. It is a very tricky and convoluted and not really comprehensible notion. Jesus told his followers that after He left the Earth, God would provide His Spirit to dwell within people who called on Him. This Spirit was meant to be the earthly presence of God after Jesus ascended into heaven. Jesus didn't go into great detail or provide any sort of manual or how-to guide. If anyone tells you that they understand all of this completely, then I would urge you to beware. There are lots of areas where we can only make assumptions.
Seeking wisdom, clarification, and truth in this area, I was lead to read the book Embraced by the Spirit by Charles Swindoll. This work was not meant to be a detailed investigation and unpacking of scripture. It was meant to be a dialog in a very conversational style. It was an attempt to help build greater intimacy in our relationship with God by giving us a few practical suggestions for seeking out or better tuning into that "still, small voice" within us so that it is more than a "still small voice". A peaceful and enjoyable book for your devotional time.