Dream interpretation is 80% scam, 20% asking you what your own dream means.
Dreams are symbolic and subjective and highly personal. Leaving aside lucid dreams and dreamwalking for a minute…
Dreams usually contain some of several pieces jumbled together:
Rehashing what you experienced in the last few days
And all these are overlaid with symbolism making them tricky to interpret unless you’re the actual dreamer, and maybe not then. What it’s really ideal not to do it get too literal with the analysis and start building castles.
So you need to ask yourself what each item and person means to you - the actual person, or a representation of something else? E.g. snakes, can be an entity, can be your own power, can represent a connection or conduit, or energy, or intelligence, or predators… etc - it really depends on the context and how you feel about it in the dream.
How you feel in-dream about it all - that is important and a big clue for your interpretation. You should ask your self, “what does this mean to me” and then follow your first impression, the first thing you think of and not 2nd guess it.
I suggest you get into meditation, go back into the dream and ask the snake/book/sibling/whatever (yes you can talk to objects) who it is and what it wants.
I’ve not really heard of people doing spell or workings within lucid dreaming.
They tend to do spells in physical conscious reality, and in lucid dreaming practice getting control of the space and what’s in it, learning to fly, visit the akashic records and generally gain information.
I see no reason why you couldn’t do spells in a lucid dream, the same as you’d do them in an astral temple, and you should be able to find your astral temple, for the same effect.
After that there’s not much difference between that and a physical spell, except that you will manifest your tools rather than make or buy them.