How is your substrate prepared? looks like sand? - but is there a nutrient rich layer below?
The 1-2-Grow plants don't have much in plant reserves as they are young cuttings that have been propagated & are now ready for the step, which traditionally means an enriched environment with plenty of light & CO2 & nutrients.
1) Add water but not to actually cover the substrate anywhere, you don't want to see standing water (this often leads to rotting of the stems etc) unless there are no plants in that area.
As the higher areas will have dry substrate, you want to flood the tank to make sure the sand/soil is thoroughly damped (with some of the aquarium soils this can take a day or two)
- it's always a good idea to fill the tank & run the filters as usual, this will allow you to adjust filter inlet/outlet so that no sand is being blown about, also look at your scape with the change in perspective that water brings (quite different than air) and see the colors in the rock.
Also note that any driftwood will tend to dry out during the dry start method so it needs to be well anchored (or have a
few rocks to balance on top 
)
3) Misting the tank - do make sure you can deliver a very fine mist of water - this is only done to maintain humidity, you don't want to see standing water on the leafs ... if you are in a dry climate, you will likely need to mist more frequently than if climate is naturally humid, so pay attention as molds can be very quick to set in
4) It's often a good idea to leave a small "hole" so that tank is not completely sealed
6) Time frame depends on the plants you've chose, sometimes 2 weeks, sometimes 4-6 weeks ... not all plants do well with this home propagation method
Which plants have you chosen?
