These rules are intended to allow you to play an OSR, in this case meaning 0D&D, B/X style games, without a Dungeon Master.
The game you will get using these rules will be a sandbox style adventure, you will not need to do any Dungeon Master [DM] style preparation although having a few stock NPCs or appropriate level would be helpful.
The normal cycle of play is that the DM describes the scene and asks what do you do? The players describe their actions. The DM describes the effects of those actions and the cycle repeats.
In solo play there is just the single character and no DM. You start by imagining your character in the game setting and play them through all the social interactions, all the NPCs and events that would normally come up. At some point you will reach a point where you would normally ask your DM for more information. Are there any guards? Are there any ways out? What can you hear? At this point the solo rules come into play. You pitch your question in a Yes/No format. The solo rules will then return an answer to your question much like a Magic 8 Ball toy. It is then down to you and your improv. skills to decide what does this answer mean right now? Often the first thing that comes into your head is the answer to go with.
If you just got yes and no answers things would get boring quite quickly. These rules are designed to throw up twists and turns into your character’s story.