Dark elf raiders lost fast to get harassing?

Si basically the title,I remember playing against them some time ago(GFF) and they where moving all the way about, I made a list and tried it against some human defense force and it was brutal how effective HDF outmaneuvered and out shot them!

Like of course but I thought they would be able to “gain” some ground at the start of the match but they couldn’t get nowhere, bad defense rolls aside i couldn’t get a single model beyond the middle of the board

I thought at least the hoverboard riders would have gotten fast but no, which is a bit odd to imagine I can get a human to move up to 9 and still shoot but the overboard guy can’t?

Admittedly I don’t know how to use harassing properly, should I do more shooting and pop in and out of cover? What about my witches? Those guys want to get in and out real close! But 3inches after seems like me just choosing where I want to be charged

Any tips? This is more of like that I want to paint some Drukhari , mainly wanted to get hellions and wyches, just for funz but they being playable is a big plus