Help required in making web page work on a web hosting domain

I need help in making my web page work on a 开发者_运维知识库public domain. I uploaded all my files & directories to root folder. How can I specify which file to open i.e. my user interface when url is opened.

I'm not sure I understand your question, but the default file name(s) that the web server looks for when you enter a domain name or directory without a file name are usually

index.htm
index.html
index.php (if PHP is installed)

(As @T.J. points out, differing additional names are used on Microsoft servers)

give a file one of these names and it will appear automatically.

Assuming Apache: take a look at DirectoryIndex