Hello can someone help,

my octavia 2025 MK4 (NX) facelift 110ch dsg (B7) is 10000km and less than one year

I found a video tutorial on then net

but that doesn't work

Sorry can not help. Why are you resetting, is it set on fixed servicing 12 months / 15,000 km and you do not want to service it?

for B7 (gasoil) it's seems to be 20 or 30000kms isn't it? I buy it new on march

They all leave the Factory set for Variable / Flexible servicing. 24 months / 18,000-20,000 miles. 29,000-32,000 km. But a Dealership or the tech maybe change to Fixed Servicing at a PDI if the car will be low annual miles / km, or maybe Fleet, or on a Service Plan. Has yours been set to 15,000 km / 372 days?