Manual Installation Procedure for PostgreSQL

Before installing PostgreSQL, ensure to confirm with Gespage support that your PostgreSQL version is compatible with the database version. 

Windows :

Go to the following page: EDB: Open-Source, Enterprise Postgres Database Management, and click the download logo for the desired version. 

Once downloaded, click on open:

Once in the installer, click next until the installation completes

You have now installed PostgreSQL on your Windows server!  

Linux : 

Go to  https://www.postgresql.org/download/ and choose your Linux distribution

Then, simply follow the listed steps  

You have now installed PostgreSQL on your Linux server!