I checked online and the manual - I guess this is TOO basic: how does one cast a spell? The only one I put skill points in is healing (level 1). It is listed in the secondary skills area but left or right clicking on it doesn't seem to do anything and right clicking after clicking on it doesn't either.
Right click (on the ground anywhere works for a self-cast like Healing). Click the right hand icon by a portrait to open the Secondary Skill menu, then left click a skill/spell icon to make it the secondary skill (re-opening the menu, it will have 'SEC' in white text in the top left of the icon); right clicking after that will use the applicable skill.
That's what I tried. I got a message saying it couldn't be made a primary skill (even though I was in the secondary area). Clicking on it did not make it the secondary skill; the whirl attack was still it.
It is the middle button you need to click, just above the potion icon... right or left hand depends on which side of the hand you assume you are seeing in the silhouette. I suppose assuming the palm would make more sense (so right/primary), but there are only 2 hand icons to check.
Yeah, the one I've been using. Sometimes, it does work (usually when I forgot I had clicked on it a while back and I'm expecting a whirl attack ). Perhaps it is working but the heal is too small to see and the animation didn't work. It is only level 1.
If you have enough mana to cast the Healing spell, there should be a sound effect and animation (blue effect around character and rotating ankh symbol above), whether it heals or not (and the only time it shouldn't heal is if you are already at max HP), independent of the skill level.
If you don't have enough mana, red text will scroll up the screen by the character saying "I need to recover magical energy" (with a couple second cooldown before it will be shown again, if you repeatedly right click).