It's hard to find some time to work on this project as it's dependent on the weather, but also free time ...
Anyway, I managed to do the plumbing in the manhole. I didn't tested with water yet, as I have a water leak in my garage just after the master valve.
I had some earth going into the pond, the level of the ground wasn't clean/leveled, so with rain, earth went into the pond.
I dig a little bit, and I have now a little progressive step, to be honest, I really like it.