Problems with the start of the car

Hello people, how are you doing? I present to me. My name is Javier, they can tell me Javo and I am 21 years old. I am new in this forum, it is the first time that I express a mechanical problem online, so they apologize if I express myself hehe.
Well ... my problem as the title expresses it I have problems with the start of my car, it is a 99 Diesel model 1.6 The issue is that when I am going to start the starting donkey it moves but the engine does not start or sticks.

OBSERVATIONS:
The donkey I don't think it is because I did it 1 and a half more or less.
The battery is fine has 1 month of use and it is a 75th moura that does not need maintenance.

I think they accrue the heaters ... but it is half difficult or some cable that is fucking me.

I don't know ... you think they are experts?

The heaters have 12+ fix with a portatil or a 12V lamp if you get the use when you contact you, if you arrive it disconnects the ramp that unites them and tries each one independently, it is not the best but you can try them with a cable with battery to the preheater terminal (where you have the twist) you pink it if you have consumption. Remember that a preheater is a resistance must have continuity if you do not take them out and probate them outside the car co a battery

Thank you very much I'm going to try and tell you how I went xD thanks for the kapo answer

Well, I already provided with the 12V lamp if the heater came running, and if it reaches them, the rather now what is not like to prove whether the heater works or not

You take out the heater, where the nut goes on a cable to the battery and you put the other pole to the metal body of the heater, if it works it becomes incandescent in 10 seconds