How did the OT Jews cast lots? I think it was to decide decisions that they didn’t have clear directives on?
Nobody knows much about Urim and Thummim, you can do word studies on the meaning of each word – Light and Perfection, I seem to remember – but what they were and how they were used is only speculation. Most think they were held in the High Priests robes, he put his hand in and picked one – but why this was and why God used it is a complete mystery. – Unless you know better to tell me?