What do you mean by abilities?
Like active? So you use it on something to slow it down?
If you mean that then it's not so hard. Dublicate an ability like Snipe or Frenzy (frenzy is pretty good for that).
That is your base ability. Just change the field "Effect - Effect" to the effect you want to apply to the target. In this case the marauder slow effect.
Same you can do with cleave - the only difference is that cleave is not an ability or a effect used through an attack, but just a normal attack. But alas! Attack damages of units are just effects too. So just change the "Effect - Effect" field to "Ultralisk - Cleave" and you got area damage.
Thinking along the lines of Ultralisk Cleave and Marauder slowing effect?
I tried and failed for both these.
What do you mean by abilities?
Like active? So you use it on something to slow it down?
If you mean that then it's not so hard. Dublicate an ability like Snipe or Frenzy (frenzy is pretty good for that).
That is your base ability. Just change the field "Effect - Effect" to the effect you want to apply to the target. In this case the marauder slow effect.
Same you can do with cleave - the only difference is that cleave is not an ability or a effect used through an attack, but just a normal attack. But alas! Attack damages of units are just effects too. So just change the "Effect - Effect" field to "Ultralisk - Cleave" and you got area damage.
Refering to a leveled ability, like the pit lords cleave from wc3.
You should take a look at this guide here, it's pretty straight forward and comprehensive.
http://forums.sc2mapster.com/development/tutorials/1696-data-wc3-esque-hero-ability-training/
Also video