Hi,
in [product_installation_root]/bin must be a sample startup script startServerBasic.sh, which could serve you as a template. It is not the recommended means of launching the server, however!
To start the Advanced Single Server Edition there is the script: [product_installation_root]/bin/startServer.sh
Another option is using the startServer option -script which will generate a start script for you, to use it for future startups.
To stop the server there is the script [product_installation_root]/bin/stopServer.sh
Here is chapter 6.6a of IBM's WAS documentation which contains the above info plus a whole bunch of advanced considerations regarding starting and stopping the server -
http://publib.boulder.ibm.com/infocenter/wasinfo/v4r0/topic/com.ibm.websphere.v4.doc/wass_content/0606a.html
HTH
wmp