Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Trundle doesnt gain much from AP heavy items. hes a beater and good at team work. early game build on HP and DMG,while using "Contaminate" to boost ATK SPD, and "Rabid Bite" to increase DMG; you'll make short work of everything in your path from the begining.
Trundle has abilities to keep the creative player alive long enough to get some high DMG/HP items like the Frozen Mallet; back that with your boots and some Armor. and your set up to wreck the game for the other team.
Spam Rabid bite every 8secs while in the midst of enemys. make use of you Pillar by Drawing enemys near your turret, Then throw the pillar behind them, to block their path and slow them down, make sure you attack them and draw their attacks. once they attack you back, the turret will do its job, and with any luck, they will have no where to go