It's 3 macros triggered by 1 button in ISBoxer. Or you can skip doing it in ISBoxer and do it directly in game by tacking on /changeactionbar # at the end of each macro. Since I haven't had coffee and I never used ISBoxer, I can't explain that beyond what I gleaned from that thread.

Doing it in game -

Create a new macro -

Code:
/castsequence [@party1target] reset=target Flame Shock, Earth Shock, Earth Shock
/cast Fire Nova
/changeactionbar 2
Put that on button 1 of your main action bar.
Press the macro. It should automatically page your main acrion bar to action bar 2.

Create another new macro

Code:
/castsequence reset=combat Stormstrike, Lava Lash, Stormstrike, Lava Lash, Stormstrike, Lava Lash, Stormstrike, Stormstrike, Lava Lash
/cast Fire Nova
/changeactionbar 3
Put that macro on button one of the new action bar.
Press the macro. Again, it should swap you to a new action bar.

Create a third macro

Code:
/castsequence reset=combat 10, Searing Totem
/cast [@party1target] Unleash Elements
/changeactionbar 1
Put this on button 1 of the new action bar.
Press the macro, it should swap you back to your original action bar.

Now spam 1. It should put you through the various macros, switching the action bar, and thus the macro that is triggered by pressing 1, every time you hit the 1 key.