Hi,
It is very easy once you learn the basics ... and you always can ask

1. extract the files and folders from the archive on your computer.
2. find the module directory - depending on how the module is packed, when you extract it, you may have MODULEFOLDER/...(some files and folders here), or may have something like html/modules/MODULEFOLDER/... To identify the module folder, look for file called "xoops_version.php". The foldar, that contains this file plus some more files and folders is MODULEFOLDER - upload to your XOOPS installation in modules.
3. Login as administrator and go to system administration. There click on "System Admin" icon and from the table that will show chose "Modules"
4. Now you should look at module administration. It will have two tables - first one is with installed modules. The second one is with modules that you have, but are not installed. If you uploaded your module ok, it should be listed here. You will have module icon, version and action - chose install and follow the instructions ...
5. After the module is installed, you will see his icon at the left part of the admin screen - click on it to configure the module.

As wizanda said: easy as 123

If you use the Documention link on the top left menu, you will find some good details on the basics like this... Alternatively the faq will also help.