right well you cant use the ammeter to read the starter current as thats much too high but you can see the battery supplying the cars systems (discharging) and then once engine running the dynamo taking over (charging).
As I said to do this you have to connect the ammeter just in the brown wire to the solenoid so first identify it out of the two small browns then work out how youre going to make the connections to both the regulator and ammeter. Remember when charging the ammeter could carry up to the full rating of the dynamo, aprox 22 amps, so the connections must be good and solid...