Adpeters selection help

Dear Experts,

Please kindly help me the with the selection of adapters .i.e.

1.what is the selection creatria with business sceniro.

2.On what basis one should decide the specific adpaters needed to be selected etc.

3.Any link explaining the creatira of selection.

I am aware of the types of adapters and there uses available on help.sap.

regards

shankar