Quick orders are available from the very start. They do not require anything from you (except your own truck, fuel, etc.) but skills. You are a driver to hire. On the right you see all available orders from every city you have explored (when completing other orders). It is good to sort them. One of the best parameters is the mileage price (down arrow). Now you can see the most profitable orders at the top. It is good to be pragmatic and pick the best orders. Sometimes you may pick up lesser order to try a new route and explore a new city.
Click on "accept order" and you will be moved to the start location automatically. The trailer is already connected and you are ready to go. Your task is to get to the destination place. Be careful with the cargo and do not damage it as it affects the payment. In most cases you do not have to bother about working time, fatigue or fuel level. Even if you have to take fuel do not worry as you employer pays for everything.
Follow the map and GPS to get to the destination place. Try to park as best as you can - you will earn additional EXP points. When you park, disconnect the trailer ([T] by default) to finish the order.
When the job is done a summary is displayed. The amount of money and EXP points depends on your level and skills. Quick orders are the only way to earn money at the beginning. At least as long as you do not have your own truck.