Hi pha,
Generic extraction - is generic one which is created by (data source name will start with Z or Y).
The data sources which are exist at RSA5 are SAP Standard data sources. for standard data source we need to follow above steps(RSA5
Line item and Delta are different.
Delta is method to load latest data from source after the last successfully load.
Nothing to worry about, lets find data sources and start working on it
if you get any issue while working on the, lets raise a discussion.
Thanjs