There are two connections here that should be addressed. First a common technique is to set threaded rod with a couple nuts and large washers into the concrete, the washers/nuts help hold the rod in the concrete. Alternatively, and much simpler although with limited uplift resistance is to drill the hole for the rod in already set concrete and epoxy grout into place. The benefit being that accuracy on site by you, rather than a concrete contractor, gives you the ability to be sure the rod is in the right place.

At the bottom of the post, simplest is a simple yoke (U shaped bracket with a hold in the bottom (for the rod) and opposing holes in the yokes vertical flanges for through bolts to hold the post in the yoke. Alternatively, there are also several "barrel nut" timber fasteners on the marketplace that could allow you to bury the connector and add "faux" pegs to hide the embedded hardware.... unfortunately the rod is fixed so this could be very awkward... ( if you can get the threads started then you have to "screw" the post onto the rod....)

If you have strong hold down requirements, variations on the threaded rod may resolve the uplift. For example the rod can have extra length, to allow you to bend the bottom 90 degrees and align and tied it into the concrete's reinforcing.