Most keys in the input file for ADF are optional. Default values apply for omitted keys. Assuming that the defaults are sensible, short input files can often be used. We will examine first the minimal input that is required to run ADF. Having read that part, you can start to do calculations.
The following input will run a geometry optimization on water, using a (almost) minimal input:
ATOMS O 0 0 0 H 1 1 0 H -1 1 0 End Basis End Geometry End
This is the input for the ADF program. You need to store it in a file, and pass it as standard input to ADF.
For example, assume you have stored the above input in a file in. Also assume that the $ADFBIN directory is in your $PATH. Then you run ADF using the following command:
adf <in >out
ADF will run, and the resulting output will be stored in the file out. If you examine the contents of this file, you will find that ADF has actually run three times: two create runs, and one geometry optimization. The fragment files produced by the create runs are saved in t21.H and t21.O, for hydrogen and oxygen respectively.