To do that, you need to have a program running on the 8051 board that will accept the data from Hypoterminal.

You can write the program using uVision, build the program using uVision, then download the program using uVision.

As Russel noted, the board has 2 serial ports:

if you use both, you can download the program via one and connect hypoterminal to the other - but you will also need 2 serial ports on your PC, or two PCs, or swap the cable between the two ports.
Of course, your program will have to be appropriately written to use the appropriate port for receiving, and you will have to correctly configure uVision to use the other port for downloading.

if you use only one of the serial ports on the board, you will have to download the program first, using uVision, then disconnect uVision and connect hypoterminal to send data.