Hi, some skills like repair, sharpen, and embellish require you to right click on the item and choose which one you want, there is no hotkey for this.
Other skills called passive skills like weapon skills 1hand, 2hand etc. and skills like detect traps, are automatically in use all the time so can't be turned on/off.
The only skills that need a hot key are the magic spells and a few basics like battlefield, teleport drop/pickup etc.
To configure a hot key hover your mouse over a avalabile skill and press a unused function key.