create /tools directory under / and then mount a filesystem on it ... see "man newfs", "man mkfs", "man format", "man mount" and "man vfstab" ... same process throughout ...

quickly ...

1. create disk slice --- use format
2. create filesystem --- use newfs
3. mkdir /dir
4. mount filesystem on /dir --- use mount
5. edit /etc/vfstab to make mounts permanent