In Destiny 2 there are two kinds of public events. The standard ones will show up on your Director, then there is a specific action you must take during that event to turn it into the Heroic version. In Weapons Exchange you fight the Fallen. First you take on a wave of standard Fallen, killing their captain. Then a Fallen Walker is flown in.
You fight the Walker as normal, taking out the legs to cause it to fall. When it does this it will drop three orbs. While the Walker is down run in and grab them. Be careful, as the Walker has a powerful stomp attack that can knock you off ledges. If this happens the orb you were carrying is lost.
Go For The Dome
Next you use the orbs to drop the force domes protecting the Scorch Cannons. It takes two orbs to drop each dome. To change the event to the Heroic mode, remove all three of the domes. This will take 6 orbs in total. Even if you have lost some there should still be plenty left as the walker drops three each time you stagger it. Be sure not to destroy the Walker before you do this, or the event will end. It’s time to live up to the events name of Weapons Exchange and grab those Scorch Cannons.
When you activate the Heroic mode, you will get a message onscreen confirming it. Now prepare, you have an extra Walker to fight! Take them both out within the time limit to complete the event. Collect your loot from the chest that spawns in upon completion.
Need some help with other aspects of Destiny 2? Be sure to check out our Destiny 2 Guide Hub.