This problem requires a relatively straightforward application of linearly superposed solutions from individual loadings. A simple spreadsheet can be prepared to give the results for the stresses associated with the separate loadings experienced by the signpost. An example is given here for the case of a solid post with a diameter of 1.12 feet:
Note that the formula for the moment about the x-axis is highlighted and shown in the formula bar above the spreadsheet. Not surprisingly, the stresses are quite low as solid posts are almost never used in practice. You may wish to begin with this case of an over-designed signpost. The tutorial contains geometry files for both solid and hollow poles. Then you will want to consider hollow poles and compare results as you attempt to optimize the post's load-carrying capacity.
You will want to continue and re-design lighter hollow posts which sustain higher stresses, but remain in the elastic regime.
Launch Ansys Workbench and start a "Static Structural" analysis in the project page as shown in the video below.