First you should get the emacs configuration file. It is in your home directory as .emacs or .emacs.d/init.el (you should use ls -la to view the hidden files)
In that file you must insert this.
(let ((buffer (url-retrieve-synchronously
(re-search-forward "^$" nil 'move)
(eval-region (point) (point-max))
This will download come congigeration packages into the .emacs or .emacs.d directory and update the init.el file. Then you should remove the above code part (only that thing) from the init.el file.
Then open an emacs window and type
Then type r to update the list. And then select package (clojer-mode) from i and install it by x.
M-x describe-variable and in the prompt type;
In that you should customize the variable to;
then save it.
Now open a .clj file from emacs.