Here is how i do it..

Download the plugin, unpack it in a directory.
upload the plugin to the ow_plugins dir of the site (make sure you do the inner folder not the outer folder of the plugin)

then go to admin panel of the site and go to plugins area and click install on the plugin display

If you have no idea how to access your website thru FTP or cPANEL then you need to contact your host, they should have explained that, its part of customer service.

i dont touch the server when i upload plug ins, i do it from the admin area, they always go on just fine, i just upload the whole folder enter htaccess when prompted and that is it, i have never had to go into the server to install plug ins

yeah understood bobbi, i just dont ever trust unzipping anything without looking at it first.  Its just a personal preference.  :)

Download filezilla and install it. Then use ur username and password to access your site and then go to "Public_html", then go to "Ow_Pluggins". and then transfer your unzipped file in this directory. And then go to Admin section of your site, click on available pulggins and install it. 

Thanks for the answers, i appreciated it so much. here's what's actually my problem..

First i chose the file to be uploaded in ADD NEW PLUG INS and  when i hit upload, it will direct to ENTER ATTRIBUTES: asking to fill up the form of HOST (what should i type here? is it the name of my host?) LOG IN AND PASSWORD (Is it my username and password the same in my control panel host) and PORT (which has a default of 21) 

i know its easy and simple for the professional out there. Hope though im not a professional, i will be one once i learn how to do it. (sorry for my english)

You are correct in all counts... use your cpanel info.  host is localhost or your domain name and port is correct.

It says Invalid Attributes. Im so sorry to bother you guys but this is the only help i know. :)

Its is no bother, but you said that you were taking care of the forum in your first message, didnt the people that your doing this for tell you how to do this..  You need to be asking them about permissions.  If they set you up an FTP with limited permissions, they did that for a reason, it really has nothing to do with us IMO.

Hi, I have the same problem here for uploading plugin...
Host is: localhost
Login and Password.. which are they refering too? I have tried all of them but dont work...
Can I use FTP instead?

login and password is typically your cpanel login and password and yes you can use ftp...

@dave,, yes I used the same login and password, but still not working.. For FTP, is there a link where I can go check out the steps of how to do it?

sure,  here ya go 

http://docs.oxwall.org/faq:how-to-add-new-ftp-account-to-update-add-plugins-and-themes