How can we create an optional index in amibroker?

hi
i want to creat an optional index with some stock.
these stock available in different industries.
how can creat it?

if i can create it i have another questions:
1)i want to have index that calculated with simple avarage.
2)i want to have index that calculated with weithing avarage.

thanks alot
habib

hello
can any one help me to reply to my question?