(1) mkdir

mkdir -p /export/home/username

(2) adduser

useradd -s /usr/bin/bash -d /export/home/username username

(3) set password

passwd username

(4) set home

chown username /export/home/username

(5) check

vi /etc/passwd
check the last line

PS: more useradd usage should see : solaris sysadmin guide

and solaris home directories