For some suggestions on books and such,
go to the FAQ's on this forum...
https://www.unix.com/forumdisplay.php...ne=&forumid=21
Since it is your own system, then I assume
you have "root" (system admin) priv's.
I'm also assuming that you SSH into your machine
as a "regular" (non-privileged) unix user.
At this point you can "become" the root user
by...
su -
...then supplying root's password when prompted.
From this point you can do...
chmod 755 [webroot]/shophtml/admin
...where I'm assuming [webroot] to be your
path set up in your web server configuration.
I'm also assuming read,write,execute for the
"owner" (the "7" in 755) is sufficient.