Set the parameters for the search function. At 4.0A resolution or better, a search step of 10 degrees is sufficient for a 10 residue fragment. The search step should be smaller at higher resolutions or for larger models. A quick and dirty result may often be obtained with a much coarser search step, as large as 30 degrees. Set the maximum range in degrees for the search.
Higher values give finer search grids, and potentially better results at the cost of time.
F obs 2 Scaling is critical to correctly fitting the density with a model. Useful to put your matches in the same region and any model you are working on. In which case you'd better have a better idea of what you are doing than I do. Grid sampling must be a multiple of 4 and obey any other requirements imposed by the spacegroup. Formfactors are supplied for H, N, C, O, S and other atom types are scaled from these.