As the title says, you can use it at the start of a timephase, but you can also use this after getting deformed or in the middle of a timephase. If you are a Saur or higher exoform some steps will need to be changed or even skipped.

Edit: This can also help you get the Everest achievement!

When you spawn in, jump towards the nearest mass spawner that is right in front of spawn and collect all the mass that it has spawned. then turn to your right and dive down for step 2. I do not suggest using the stair boosts. If you have already spawned, just get to the mass spawner in front of spawn, collect the mass it has spawned, and go below the lightbridge to the right of spawn.

There will be a trail of mass leading to the inside of a building, collect all the mass in the path and enter the building it leads you to. Make sure you are moving away from the mass spawner so you don't go into the wrong building. If you are superior you will have to go to the biggest opening of the building to do the next step.

There will be a mass spawner inside the building, just like Step 1, collect all the mass that it has spawned. You will probably notice a little hole in the building's floor/wall, this will lead to the outside where there will be a trail of mass again. it will lead to an open area with a big building in front of it. After collecting all the mass in the trail go to the nearest stair booster in front of you. Make sure you are moving away from the back of the map. you can choose not to collect the trail if you are at Prime exoform or higher.

Now that you are at the stair booster, use the stair booster. If you are Saur exoform or higher you can just double jump instead.

Land on the nearest mass block that is on the building in front of you. You can press C while in mid-air to fall down faster, if you have default key bindings of course, and i'm pretty sure you have to press the bottom button for controller. (Xbox A button i think) Then collect the rest of the mass in the trail.

On most maps there will be a staircase in front of you. If you are in a map where this staircase doesn't exist, skip to Step 8. Go up the staircase and collect all the mass in the trail that will be in front of you. then turn to your left and do the next step.

There will be a floating trail of mass with a launch pad below it. Go above it and press C to make this faster, you will most likely now be Saur exoform, so the launch pad won't work. If you did not become Saur just ignore being launched into the air and continue with Step 8.

Now do whatever you can to earn more points/mass and continue playing the timephase like normal. Example: In the map i was in when i was taking the pictures (i'm pretty sure the map was called Limbo) there was a mass spawner right in front of me, so i went towards it and took the final picture, before devouring all the mass.

Now you know how to get a bunch of points/mass at the start of the timephase. Please consider giving me an award because i just sacrificed my almost guaranteed 1st place for every timephase. If you have any questions just ask in the comments and i will eventually answer.