Have you read the uVision Getting Started guide yet, as previously recommended to you?
http://www.8052.com/forum/read.phtml?id=72589

You really do need to read this first, and work through the example projects in it
This will give you a proper introduction to the tools.
There is no point in trying to build a house before you have dug the foundations!

In fact, the very first example in Chapter 7, Sample Programs, does precisely what you need - it is a simple "Hello, world" project that shows you how to send serial data using the UART.
It also shows you how to use the debugger to see what's going on.

Once you've got this working, then you can add receiving characters.

Then you can look at these examples for interrupt-driven serial IO:
http://www.keil.com/download/docs/intsio.zip.asp
http://www.keil.com/download/docs/intsio2.zip.asp