Here’s a quick step-by-step guide of the installation process. You may also check osclass installation guide for version 4.x:
https://osclass.osclasspoint.com/installation

Step 1

Download osclass installation archive into your computer. You may find multiple archives, however we recommend this one:
https://osclass.osclasspoint.com/download

Step 2

Unzip archive you’ve downloaded into your desktop. Osclass files are located in folder Osclass-master. Go to this folder and copy whole content (files & directories) into desired location on your server.

Step 3

Execute the Osclass installation script by accessing index.php or oc-includes/osclass/install.php from your browser:

Step 4

Follow the installer’s instructions.

Step 4.1

Make sure the server has the required permissions to write in the files and directories specified. This will allow you to create a basic configuration file as well as upload images, documents, etc.

Step 4.2

Add your access details to the database. If you haven’t created it yet, the installer will ask for another account with permissions that will allow to do it for you.

Step 4.3

Add the basic installation details and select your classfieds site’s reach: international, local, regional…

Step 4.5

Your installation is finished! Use the automatically generated password to access your admin panel (/oc-admin).