I suggest you read the FAQ UI Overview first, to get a feel for the options and the User Interface.

As soon as you logged into your account, search on the map for a place to start your emergency services career. Start in a big city or in a rural area, start where you like, it has no effect on the spawnrate of the missions.

We suggest you to start with a fire station, since that's where the most money is at the start.

Place one of the stations where you like, but remember: the bigger the street, the higher the maximum speed of the vehicles. On top of that, a station has to access at least one road.

Soon after building your first station, which automatically has a unit and some employees in it, some missions will generate around it. Now on you can start sending your newly aquired units on missions.

For more information and tips and tricks you can go to the forum:

US: https://board.missionchief.com

UK: NYA