no, powerwash the furs clean ( this is much easier than fleshing by hand), the mix half borax and half alum powder together and add a few ounces of water. you want a thickness similar to mashed potatoes. I've copied the alumni use below
https://www.amazon.com/dp/B07M8DLW9T?ref=ppx_pop_mob_ap_share
Depends on whether you are hard or soft tanning. Hard tan is easier and only requires borax and alum paste. Soft tan uses any variety of chemicals to put "clean" oil back into the hide so it can be made into garments etc.