"reset to step 1" bound to assist key

Greetings all,

I've been using Isboxer for 2 weeks now, so i'm quite new (not to multiboxing), and I'm currently setting up a team . . .
The problem I'm facing : I'm struggeling with reseting a spell rotation to step 1. Let's take as an example my fire mage :

This is my desired spell rotation :
- Cast 5x scorch (=7,5 sec). This applies a debuff that stacks 5 times, and lasts for 30 seconds.
- Cast 8x fireball (=24 sec), then recast 1x scorch (reset the debuff cooldown)
the second step must be repeated until the mob is down.

So, I created a 2 step rotation.
STEP 1: a keystroke action to cast Scorch, with "do not advance to next step for at least 7,5 seconds" (=5 casts)
STEP 2 : It's a castsequence macro (8xfireball, 1xscorch), with "do not advance to next step for at least 900 seconds". That's 15 minutes, enough to never go back to step 1 before the mob dies.

Now, the problem is, I need to go back to the first step when I pick a new target. I've searched, and I've read you can bind this reset to the assist key. (firescue17 explains that he did it in this topic, but he does not explain how it's done).
My assist is in the "non combat" keymap, and it's a "assist me" mapped key bound to numpad 2, which sends the "/assist {FTL} maccro to "all other".

Can anyone help me to understand how to do this?

Thanks in advance for your help.

[lax]

1. In the top left pane under Key Maps select the one your key is in -- Non-combat
2. In the bottom left pane under Mapped Keys expand the one you want to change, and select Step 1 under it so to the right you see Actions, with stuff below it
3. Right click Actions to the right, and under Key Map Actions select Mapped Key Step Action
4a. Set the Target to whichever Window(s) should reset
4b. Select the Key Map and Mapped Key to reset
4c. For the Step Adjustment, use "Set to" with Step 1
5. Export to Inner Space

This is precisely what I needed, thank you very much