What you need depends on your selection of EVSE. For instance, if you operate the stock Honda charger at 240V then you only need a 20 Amp circuit (note: This is not officially sanctioned by Honda, but it has been proven to work by others). If you want to take full advantage of the Clarity's capability, then you need a 40 Amp circuit (and corresponding EVSE).
Since the labor to install an outlet generally exceeds the cost of materials, many people install a 50 Amp 240V circuit with the NEMA 14-50R receptacle. This is commonly used to connect RV's in campgrounds and most EVSE's are directly compatible. This will exceed the need of the Clarity (some refer to this as 'futureproofing' because it may also support a future vehicle). This sort of EVSE (there are many) will cost in the $400-$600 range.
Although it seems shady to me, it has been reported that some electricians charge more if they know the job is for an EV. There is NO reason for this to increase the cost, so it has been recommended to not tell them what you need this for (or, tell them it is for a welder for example). Just tell them you want a 50 Amp 240V outlet installed in your garage (with the NEMA 14-50R receptacle).
The price for this installation can vary greatly depending on your circumstances (location and capacity of your power service and relationship to the garage). It usually makes sense to get multiple quotes. It can range from a few hundred dollars to a couple thousand.
As for which EVSE to buy... There are many to choose from. Browse around this forum and you will see people advocating for one kind or another. They are pretty much interchangeable so look for features that you like. Some have 'smart' capabilities that can connect via WiFi and report energy use. I have a JuiceBox (it has WiFi capability) and I have really liked it.