A method of installing software on and/or testing a computer system includes reading a plurality of component descriptors from a computer readable file, each component descriptor describing a respective component of the computer system, reading a plurality of steps from a database, each step being associated with a component descriptor and including a respective sequence number, and sequencing the plurality of steps in a predetermined order according to the sequence numbers to provide a step sequence including commands for installing software on and/or testing the computer system. The method further includes determining for each step read from the database, from data associated with that step in the database, if that step is incompatible with the presence in the computer system of a component other than that corresponding to the component descriptor associated with the step, and if so, discarding or not discarding the step according to further data associated with that step in the database. It can also be determined if that step requires a parameter, and if so, calculating such parameter according to further data associated with that step in the database.