Hi @Sirapa. Nice to meet a fellow sculptor. Your work is great. Sand is a great material and the main trick is to compact the sand into a solid block before carving. I have done some posts about the process. You can check out.
https://steemit.com/art/@ammonite/apathy-part-1-compacting-sand-sculpture
https://steemit.com/art/@ammonite/apathy-part-2-sculpting-sand-sculpture
These was pretty large scale project but the same process is true for working on a much smaller size. A bucket with the bottom cut off could be used as a form to compact the sand and my tools are palette knives that you would use for painting.
Any other help I can give you to get started just let me know.
I'll be watching out for you work.