Unix assumes many people will be sharing a system and uses file ownership and permissions to keep people from walking on each other. Each file and directory generally has 9 permissions. Using the -l switch for ls might give something like:
|-rw-r--r--||1||withers||staff||10161||Sep 19 07:40||.cshrc|
Taking a closer look at the permissions:
Other info tells us it is a regular file,
user permissions are read, write, no execute,
group permissions are read only,
and other permissions are also read only.
Change permissions using chmod. There are nerdy ways to use an octal mask to set permissions but it is easiest to do something like chmod ugo+r .cshrc to give read to user, group, and other. Be very careful about giving write and execute to group and especially other else you could not only lose your own data, but cause others to lose theirs.
Please note that you must have execute permission on directories in order to cd into them, you must have write permission in order to move them or create files within them, and you must have read permission in order to list whats in them.