Custom GPT Chatbot for a property management company- Help Needed!

I am new to the developer forum but have been using chat gpt for awhile. I was recently hired by a commercial construction company and have been working on creating a chatbot system for our website of our apartment complex. I am hoping to find some guidance on how a system like this would be created. We want to make a system that can chat with potential future residents. If anyone can help, let me know. We can provide payment upon assistance!