Once you have controls, you can destroy several objects here to gain some studs but I do suggest to just play normally until you have the chance to gather the multiplier blocks, which can easily and quickly rack up your score.
Press Square to attack and press X to jump. Beat 5 orcs with banners, then beat 3 orcs with shields. Mash on Square to remove the shields from the shielded ones. Hold Triangle, then choose Elendil to bring down the towers and beat the orcs on top.
The fight with Sauron is very simple. Just use Elendil, run around to avoid his strikes and wait until he slams his weapon to the ground. Once his weapon gets stuck, slash it three times. Beat the orcs entering the grounds to regain hearts.
Use Isidur to take out the orcs and destroy the lava rocks. Jump across the platform. Continue by jumping up the bars and shimmy to the right. Destroy the boulder to reveal the ramp. Switch to Elrond to jump higher and push the boulder below. Switch back to Isildur and destroy the rocks again. Continue jumping across and just take out the last batch of orcs in front of the gate. On the next screen, just cross the bridge.