Partitions, home and root proportions and making one bootable?

When partitioning a HDD for slackware 32 bit, how big should home and root be? I understand swap. And which is bootable, home or root? I think it is root? And the size is determined by the amount of software that goes there later?

This lesson in around minute 6 eznix does partitioning, but differently to me because he is using VMware:

https://www.youtube.com/watch?v=mWKEPBsIgVs&t=370s