At the start of the fractal four grawls have to be killed in order to start the first event. Use Pull
s to group them up and quickly burst them down.
The next event requires to fill up a progress bar. For every grawl killed the party gains progress. Note, that the grawls always spawn in groups and can be attacked before they are visible. They always spawn at the same spots, so you can focus AoE damage on these spots.
While four people kill the respawning Grawls to fill the progress bar, one person (usually the Renegade
but anyone can) should run ahead to the next area and trigger the checkpoint at the Grawl Shaman
. This way, everyone can portal after the section is completed and resurrect to skip the Boulder passage.