When all input parameters for the selected simulation type have been defined, save the project, and then start the advanced solver by clicking Runner on the Operations ribbon to open the Runner task panel.

When you are finished changing the settings of the iterations, click Start to run the advanced solver and view the status as the solution proceeds.

While the simulation is running, you can save a copy of the current project using the Save a Copy… command in the System Tool   menu. The copy will open in a new tab. You can then make modifications to the new project while waiting for results. The file name of the copy is the original file name incremented with a number.