Crolson, welcome on JWN board. Most of us here are ex-JWs who left organization recently or long time ago like myself 21 years ago. There is no universal consensus of JW doctrines and beliefs because they change all the time. The WT is not the same organization I grew up in in the 70's-90's, so what we studied and believed 25-35 years ago is no more relevant today in WT world. So whatever you miss on any doctrine, JWs are not afraid the loss of the knowledge, because a new doctrine will arrive shortly. I can only answer some of the questions that I remember from my WT life back then. There are probably others who can answer you better.
- What is your God (Jehovah) like?: Creator a life giver and the only One who was always present
- Where does your teaching come from (which writings)?: Bible interpreted through WT publications. In the 1980's it was later forbidden to study Bible on its own as it could lead to heresy.
- Who is Jesus? Is he God or man or both? Did he save us from our sins?: Jesus is not God. He is only mediator for 144K and nobody else. He only save 144K. The big crowd is saved through association of 144K.
- What does it mean to have salvation?: Nothing. Salvation for Big Crowd is achieved in the ability to ride through Armageddon, doing field work, and read WT publications. 144K goes to Heaven.
- Who or what is the Holy Spirit? What is his function?: A force that created universe and guides FDS.
- What happens after death? (both for faithful JWs and for those who don't believe): With exception of 144K, nothing. Death is sleep, a status of non-existence and lack of awareness. Evil people or faithful JWs of Big Crowd get resurrected as nothing in their past lives mattered. People destroyed by Jehovah do not get resurrected (flip-flop doctrine). 144K see their funeral on their way to Heaven.
- What is sin? What can we do about it?: Sin is fall of man from Grace; inability to be good. Person is born damaged with a sin due disobedience of Adam. JWs believe in Original, Adamic sin. We cannot stop to sin, as it is part of our human nature, but we can mitigate the effect by doing field work, read WT publications, and attending KH and numerous conventions.