Hello, I am doing a project with an Arduino and a water pump.
What I want to know is how to control when the water pump opens and closes. I want to know the connection that I would have in the Arduino. Because my intention is that when I press the start button my pump starts. If someone can guide me in the part of the cable connections I would be more than grateful.
I'll send you the water pump and the connections it has. 
If someone can tell me the connections to connect the cables to the Arduino, as well as which ones go to the battery
This tutorial looks adequate. Use a 20A power supply.
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That pump nameplate says it needs 18 AMPs max so you'll need to get both a relay and power source capable of at least that much current. The red wire from the pump goes to the + Positive side of your 12 VDC power source, and the black wire goes to the - Negative side. The relay contacts would be wired in series just like any other switch. Be sure to get a relay board with a buffered input to take the low current from the Arduino and boost it to drive the actual relay.
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As well as these suggestions, keep in mind the thickness of the DC power cables. - rated for 20A peaks.
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Thanks for answering, I would like to know which of the cables would be going to the relay?
What is the actual purpose of your project? I wonder because your pump already has a pressure switch that will shut the pump off at 60psi. and turn it back on when the pressure drops. The pump is for an RV water system, like for a travel trailer, etc.
You need an automotive type relay that can switch 30 Amps (like those for a winch) and a second relay or transistor for the Arduino to switch the first relay.
You didn't say which Arduino.
Bosch relay
Actually the current draw will be based on the back pressure on the pump. If free flowing, current should be <8 amps or so.
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There seem to be two free leads, one red and one black. Plus one red one already connected between the pressure switch and the pump motor. I'd connect the free red wire to the relay contact and the other relay contact to the positive side of the 12 V source. Connect the free black wire to the negative of the 12VDC source.
Here's a relay rated at 30 amps that should work directly from the Arduino.
Why would you need an Arduino???
Hello, I'm doing a project, and I want to know if you know the correct connections to make a mosfet work with a water pump, since I want to control it with an Arduino. I'm leaving some photos here so you can see.If you could guide me to make a correct connection
The time you spent drawing those little arrows could have been used to sketch out a clear schematic on paper, take a well lit photo, and send that.
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I expect things to get smoking hot, so avoid touching the MOSFET when it is powered. On the first try, a short between the drain and gate will likely damage the MOSFET.
Post an annotated schematic showing exactly how you have wired it, including all connections, power, ground, power sources, and other components. Additionally, provide a link to the motor's technical specifications.
If you have started writing code, post that as well.
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Be sure to include the exact pump model number, and or ALL the information on the ratings plate and/or a link to the exact pump at the manufacturer's web site; ditto for your power supply for the pump; also include the exact part number of that MOSFET, so we may ascertain whether it will be suitable for the job.
I'm sure there's more we'll need, but start with that.
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Thank you for being kind, I will try to make the connection diagram, it is the first time I am doing a project in this way. I also have to clarify that when I press a button, what I would be doing is through the Arduino to make a stepper motor work and at the same time I want the water pump to turn on. The code and the motor part are already ready. What I am having doubts about is the connection with the water pump since I want to control it through the Arduino.
At this point you've allowed two previous threads to die without responding to posts from others.
Should we expect this thread to also die unresolved?
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Hi, I'm just trying to resolve my doubt, and as I told you, I already resolved the problems in the previous forums. Now it's a totally different problem. I'll try to answer the messages and let you know if it's resolved. I'm just trying to figure out if someone has the knowledge to help me. 
And we're trying to figure out what it is you're doing in detail. But, detail continues to be lacking.
To give good advice requires that we have some confidence about how you're doing the job, not just that your doing it. There's a million schematics for wiring a MOSFET on the internet, so grab one, sketch your circuit particulars around it, post that sketch, and maybe you'll get some advice.
Yes, that is exactly what I am doing, as I just answered another person. Right now I am making the connection diagram. I will be passing the connection diagram soon. Thanks. 