how to ping abilities?

The easiest way is to hold down control and right click it. I personally find control easier than G as G is in the middle of the keyboard.

G is the default to ping..... press G and click, hold, and slide it one of 4 ways, or press G and just click to put a dot on the minimap for a few seconds, or press G and click abilities, your health bar, items, mana, etc and it will ping those.

press control, g, or alt and click on the ability icon.

Also you can ping timers by pressing tab and just clicking on one of the timers at the top (that was a bit better explained in the patch notes but figured id say that too)

I know it's been 2 years but for anyone who's looking for the answer: The thing is this CTRL + click is shared with Quick Retreat ping, I've moved the classic Retreat Ping keystroke [V] to Quick Retreat Ping [CTRL + LMB]. After that those pings that were supposed to be CTRL + Click on UI, etc. moved to [V].

In other words, if you set Quick Retreat Ping from CTRL + LBM to anything else ([V] in my case) you will trigger that ping by hovering a mouse on ability and then press the key ([V]). Or you can remove Standard V key binding and move to a Quick one, so you get V as a quick option to ping retreat and CTRL + click as an option to ping your abilities and item.