The Holy Spirit has always been the most mysterious of the three persons of the Trinity. The Father and the Son are relatively simple to understand, on a basic level at least. God is God, the Creator and Father of all, and the Son is Jesus the incarnated God and Saviour, but the Holy Spirit is not something that is so easily defined or which can be pinned down in any clear way. Part of the reason for that is that the time of the Holy Spirit has not yet fully arrived except for a few individuals here and there. Awareness of the Holy Spirit is something humanity needs to evolve towards because it is not out there but in here.
God is transcendent and he is immanent too. The Holy Spirit is God Immanent. It is God within us and one might go so far as to say that for a perfected soul it is us though with the proviso that this does not entail an absorption into pure oneness and loss of self. But the spiritual goal might be defined as reaching a state of complete union with the Holy Spirit which means bringing one's individual nature into complete alignment with God as he is within our own soul.
The Holy Spirit is God as known subjectively. It is intuitive knowledge, spiritual love and total freedom. As such it is the opposite to outer authority whether that be religious, political or that based on any earthly image of God (most religions end up, however they start, as serving an image of God). But until we are in the position of being able to respond correctly to the Holy Spirit, through personal spiritual development gained through self-purification, cultivation of imagination and increased spiritual sensitivity, alignment of personal will with the will of God meaning his purpose in creation, then we may need the guidance of authority.
The usual cautionary notes apply both with authority and with inner understanding. Authority must be both legitimate and uncorrupted as far as is feasible. Now, for instance, it is neither. And inner understanding must also be legitimate and uncorrupted meaning not contaminated by ego, prejudice and opinion. This is a hard task but achieving it is part of the spiritual path, the part that makes authority our own though, of course, it is not our personal possession. We have just brought our soul to the point at which it can be filled with the Holy Spirit, and the authority is that of the Holy Spirit.
In the modern world outer authority is dead. There is none legitimate but that is a necessary phase required so that we may build our own inner authority. Increasingly, we will find that we have to build a spiritual understanding and awareness quite independently of any outer structures, in fact often going against these outer structures. This must always be done with humility but also with strength and determination. You will not build spiritual truth into the fabric of your being if you do not learn how to stand against the world. So, have confidence in yourself but also submit yourself to God at all times remembering it is never you who achieves these things but God in you which is the Holy Spirit.
I don't wish to be reductive and say this is all the Holy Spirit is but from the point of view of our immediate needs this is exactly what it is. The Father and the Son are beyond us but the Holy Spirit is within us. However, remember these three are one. That is a mystery which cannot be solved by the intellectual mind but with the aid of the Holy Spirit we can come closer to an understanding of what it means.