1) remove the grip. The Leshiy OEM grip has a little cover you need to pop off to get to the 4mm (I think) screw.
2) cock the gun, and leave it open... no need for a pellet. You can dry fire so long as there’s 150bar +
3) back out the screw behind the trigger and put it to the side. Take a visual note how far it was in as you’ll need to be a little father out as your starting point. The idea of this mod is the first stage takes you to the contact point of the ball. The 2nd stage breaks within the space of the ball plunger depressing.
3) slowly, really tiny turns, move the screw out. Test each turn by dry firing. The first pass is about getting to the first stage without the gun firing.
4) if you went to far, the gun won’t fire. So back it out with tiny turns.
5) there is a very small amount of wiggle room (a 1/4 - 1/8 of a turn where this mod works. Within that space you can play with how heavy that 2nd stage is.
Note: the trigger might not be fully engaging. It either requires you to fully open to the point you engage your safety, or with that light tap (while open!) to get it to engage. That’s fine for now... that’s what the next part is About.
6) now that you have that working, you need to remove the trigger guard. See pics above.
7) start with a spring (8mm OD) about the length of my pic above. It requires more tension than you think. Pushing the trigger guard back down with a single finger should take a little effort. While doing that, put the screw back in place that holds the trigger guard down.
These 2 pics are a good reference point for where it should go. Note though, I was using 2 springs here... 1 to hold it upright and the other serving as the tension needed to push down on the sear. I've replaced this with a single 8mm one as I mentioned above.
Test the cocking mechanism. If you have the spring right, it should cock about 1/2 way or so as you swing it open to cock.
Note: you may need to adjust the ball plunger screw again slightly after this. Even putting the grip back on can impact it slightly.
Lots of tinkering and you’ll get it.
Here's a video a user submitted he found on youtube showing the visual of what I describe above.