If you have the Owner's Manual, it will tell you what the codes mean. You can also register your Honda with "Owner Link" to get a lot of useful information. I think all you need is the VIN to register.
Change oilRotate tiresChange transmission fluid
Oil Change
A code 10 is a Iat sensor. Intake air tempature sensor.
A 1 Honda Civic 8th Gen. : Oil change + Tire rotation
It means: Oil & Filter change and a Tire Rotation
what does a service B12 mean for a Honda Civic Sedan
b15 is the type of engine block that is in your honda
Check your owners manual but I believe its a maintenance reminder for your oil to be changed.
Trouble code P0847 means:Transmission fluid pressure sensor/switch "B" circuit low
B12 means you need an oil and filter change, tire rotation, and air filter replacement.
Trouble code P1456 means: EVAP Emission Control System Leak Detected (Fuel Tank System)
Trouble code P0303 means:Cylinder 3 misfire detected