I have a problem getting to a disk location.
/dev/md/dsk/d7

When I login I'm at
/opt/users/*******

Please suggest a command that I can use.

Use df to find out if (and where) that disk is mounted.
If not mounted you need to mount.
then use cd (change directory) to get to it.

Thanks of the info. I've gotten to the actual dir, how do I go into the disk.

How do you list content of a disk
P.S.
/dev/md/dsk/d7 156701368 152235403 2898952 99% /data
I need to free up some space.

find /data -ls

But you might want to start with the du command to find the directory/file with the largest amount of data. Then repeat the du command for that large dir etc.

e.g.
du -ks /data/* | sort -k 1,1n