It is important to note, that you can't assign all skills to the LMB, the ones you can are mostly skills with no cooldown, these are considered basic attack skills. Hitting with a melee weapon or a staff, shooting with a ranged weapon or a wand. The left mouse button, will have an auto-attack assigned to it, which can only be assigned to the LMB, and is basically a very simple attack with a weapon. You can grab a skill from the Skills panel by left clicking on its icon and dragging it to any button, or just right click it on the Skills panel to automatically take it on the right mouse button. On the mouse buttons, you can assign skills easily by simply left clicking on the skill places representing your left and right mouse button, which brings up a list of the possible skills, left clicking on one will choose that. ' J' stands for Journal, the prequel's Arcane Statistics panel.Most of the panels are opened with the key of the letter they start with: You can open the panels with both the mouse and the keyboard. The keyboard is used to some specific jobs, like Shift is for standing still while attacking and the buttons from 0-9 can be assigned to skills as well.

You move your character with the left mouse button, and you can assign skills to both mouse buttons, in its default setup the right mouse button already has one skill assigned. Torchlight II is played with a mouse and a keyboard - and definitely not with a gamepad -, focusing on the mouse. ControllsMost of my readers won't have any problem as most Torchlight II players are already experienced hack'n'slash gods/goddesses of war, but in case you are less experienced, here's a 'small' note:

Torchlight 2 walkthrough