Like BigSis, I did my 4th and 5th step with the guidance of a wonderful sponsor who had been through all the steps several times herself, and who I could trust with anything I shared with her.
Like you, I didn't understand it, and I couldn't do it well until I really had a deep grasp of Steps 1, 2 and 3. There is a reason the steps are in the order they are in, and taking as much time as I needed to understand and build each one helped me with the next.
Defects? Me? HAH! I thought that I was a victim of everyone else's defects, but then took time to see how I had been affected and what it had brought out in me.
Resentments were the biggiest. I too had snooped, manipulated, tried to control, and felt anger, sadness, bitterness and shame at all that had happened and lived my life in fear. And most of all I had treated myself badly, allowing myself to isolate, lie to myself, and get angry at God for the bad hand I had been dealt.
Surprisingly, as I went through my childhood I could find deep rooted resentments with people who maybe meant me no harm but who had instilled in me feelings of distrust, anger and fear.
Like BigSis, I made a list of each person in my life, what had happened and how it had affected me then and how it affected me today. Once I began writing this out, the list grew and grew and I discovered resentments I didn't even know I had.
I didn't have to justify my feelings, I simply had to write them down and then see them for what they were and decide if I wanted to carry that baggage around with me the rest of my life, or turn it over to God and be done with it.
Also, like any inventory, I listed the assets, the good qualities about myself, especially gratitude for how far I had come.
Also, from reading your post I thought I should clarify...these are not the steps where we make amends. That doesn't happen until steps 8 and 9. Right now we are just looking at who we are and how we got that way, and the things we would like to change.
Many people fear Step 4 because it takes them back and to places they no longer want to go. For me, I found it refreshing because it cleared up many answers I had sought and helped me get to know the person I really am.
Hope this helps a little. Take your time and if you don't feel ready then maybe go back and work on Steps 1, 2 and 3 until you feel ready to face this self-analysis step.
Hugs