Its generaly good iadvice except it isnt
First of all if u want to play mage you need first to finish game as a warrior or priest to know what is where , because mage is very weak at begining. Then Its easiest to start with wands , because you can use shield with them and that helps a lot. After making few levels and selling wolf pelts you can buy wand from wizard tower near nivarian or go to quest island from port arthur and get beatrax wand. Both of them are fine for starters. geting 1 point of mage barier is fine but what you need most is to max wand mastery and 2 levels of lesser sumoning also helps a bit, then you need to do 3 quests for wizards to have enough rep to learn fire golem. That are to bring 2 marples (can steal them from lesser wyverns) bring 3 ice (or maybe frost?) salts- just buy them from random encounter merchant, because its random drop and can be dificult to get if unlucky, and to bring white wolf pelt and 1 small ruby to the guy in Kingsbridge. Now you can learn fire golem from freetown mage guild and game starts to be quite easy. Later (when you kill troll boss and trolls in arena) , so around level 17 , simply respec for staves and iron golem, and from then that guide written above is correct, because its a best mage spec.
Also if u didint realize it yet its best to give almost all stat books not to yourself but to Grisenda.