Just add effect tag inside the empty <for></for>. As you can see from the example, the values are taken from other table, so you can copy that table as well (the table is because, each lvl of the skill, there is other value, but since your skill is lvl 1 you don't need it) or change the val to a number when you want all lvl add the same amount, or your skill lvl is 1 (for correct value, look at table Tab-runSpd, it's 20 and 30, so at lvl 1 its adding 20 speed and at lvl 2 it's adding 30). Ofc I am talking about the <add order> line :)
<effect count="1" name="Buff" time="1200" val="0" stackOrder="#Tab-runSpd" stackType="SpeedUp">
<add order="0x40" stat="runSpd" val="#Tab-runSpd"/>
</effect>
I guess I was clear, if not just ask :P