How to limit new user accessing other files?

If I create a user account by using "useradd" and "passwd" under root in
Linux, how could I limit the user to access other files and avoid disasters
if they access our server through SSH ?

lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.