There is no requirement of setting CATALINA-HOME.
Follow below instruction .
Right click on computer --> properties --> Advanced system setting --> Environment variables.
User variables section --> click on "New" --> variable name : CLASSPATH , variable value : D:\java\lib*.;D:\tomcat8\lib\servlet-api.jar.; --> Click "Ok"
New --> variable name : PATH , variable value : D:\java\bin; --> Click "Ok"
System variables section:-
Click on "New" --> variable name : PATH , variable value : D:\java\jre --> Click "Ok"
I've installed java and tomcat in D drive henceforth the locations above are under my respective paths.
Give location paths where java and tomcat are installed in your PC. Thank You