I need to add new modules to an already designed site. Where do I find these modules and what do I do with them after downloading them from the XOOPS site? The new modules I need are:
1. E-newsletter: to post e-newsletter files in pdf
2. Contact us: for contact information
3. Article tracking for e-journal: where authors can track the status of their articles

Thanks for any info

If you want to send the pdf files in an email, you could try "Diffusion Center" I've no idea how easy it is to get working right, there are apparently some issues. Alternatively, you could send a link to a pdf file hosted on your site in an email...
Newsletter mods can be found in the Module repository here.

Contact modules can be found in the Module Repository here.

Not sure what you mean by "track the status of their articles". Do you mean compose an article, or see whether their submitted article has been authorized yet?

thanks for this info. i will try the modules.

as for the tracking, what i mean is this: as the one handling the different life stages of the articles, we would like the authors to see what stage their articles are now in. so that means i have to update it and they can access it through their user id's. similar to those postal tracking system i guess.