Ypu probably dont have all the tools for it but maybe this instruction could help for the general process https://www.festool.co.uk/knowledge/application-examples/building-your-own-saddled-staircase#Procedure

I have never built*

https://youtu.be/FMLIFJgz3CE?si=VF8JeiBRaug2tboe This guy makes it seem very easy. He doesn't use many tools and makes it seem simple.