It depends on the model, generally models are generated in Rhino 3D. The supports I use either version of B9 creator that has been set up for the D7, or Creation Workshop, or Nanodlp. Then I download the the STL files into Nanodlp that is running on a raspberry PI for printing. Depending on the model I may have to process the STL file on my desktop, then download the prepared file to the PI.
As far as preparing the printer just turn it on, make sure it has resin in it and just print. I have had resin sitting in the printer sometimes for a couple of weeks between uses with no adverse affects. Post printing just rinse between IPA and soapy water, then depending on the items use determines whether I post cure with UV.