Welcome to the forum @Savelugu_MEO_GES and thanks for adding your profile picture. It helps build community! We're glad you're here. When you get a chance, please introduce yourself on this forum thread.
How is your website hosted? In addition to a domain name (which you have) you will also need a server to run the Central software. The documentation has the full instructions: https://docs.getodk.org/central-install/ - it sounds like you have completed the first step of Getting a Web Address (Domain Name).
I'm not sure the best way to run Central on the same machine that you are already using to host your website (if that is what you are asking) because Central sets up its own things like nginx and a database in docker, and those can conflict with existing webservers and databases on the same machine. I think it's possible to do it, but would require changing things from the default Central setup. Even though I work on Central, it's not clear to me what parts should change to accomplish this. This other post about Central's nginx conflicting with the host machine's nginx may have some clues.
It is also possible to run Central on a separate machine with a different IP address and have the subdomain point there. I think this is the "recommended" approach. That would require more resources (running another server dedicated to Central), but the Central setup would be straightforward, and if your Central server were to experience a lot of traffic, it wouldn't affect the main website. This part of the docs describes Central's performance on the specs of a low-tier Digital Ocean machine.
First of all I want to thank Danb Joseph and Kathleen Tuite for your response to the above to subject I posted for support. I have appreciated and very grateful to you. My name is Yahaya Baba Ibrahim from Ghana and I am working at Savelugu Municipal Education Directorate as Monitoring, Data Collection and Statistics Officer. Danb Joseph, on my post with regards to subject above "Use my website domain to create Self hosting server in ODK Central". The website I posted https://smedges.org is hosted in Hostinger business hosting plan and has server, IP address, database and others. I read your replied and I am very grateful for your efforts but I don't actually know exactly what I can do to install the central into my website server per the explanation. Please, I need further guidance to solve this problem. Thank you.
Also, Kathleen Tuite, on the same subject above, thank you very much for your reply. You were right for that explanation. I actually want to know how I can install the odk central into my existing website server to carry out my work without using different server. I would be very grateful if you could find out how it works and then guide me to do it. Thank you.
Hi @Savelugu_MEO_GES, we are glad you are interested in ODK. The folks on the forum volunteer their time, and we try to answer questions as possible. Generally, we ask that people try to do something themselves, and then come to the forum with specific questions when they run into an issue. We can't help you with a fully unique setup specific to your situation. If you have specific questions about specific problems you encounter, we will do our best to help. If you would like to hire someone to help you with a larger ODK project, you can try posting in Marketplace.
The core team provides extensive documentation including installation instructions for a standard installation. They cannot provide the details for every possible installation type. Another option for organizations is to pay for hosting (and support the ODK project) by purchasing a Cloud ODK plan as detailed on https://getodk.org/.