Simply add the html carousel code in the home page where you want it to appear. 

These links may be helpful for you

• http://learn.elgg.org/en/1.x/guides/themes.html#view-extension
• http://learn.elgg.org/en/1.x/guides/javascript.html
• http://learn.elgg.org/en/1.x/tutorials/hello_world.html

This tutorial gives you basic instructions on how to save data to the database: http://docs.elgg.org/wiki/Tutorials/Blog

For extending views and changing css it might be better if you start a new discussion topic for each particular problem and describe in detail what you are trying to achieve.

Also there is an official book on Elgg from the core developer Cash Costello written with simple instructions and pictures.

At any time if you need  any support you can use this community help.

thanks 4 replay!!