An inverter converts a steady stream of electrons (direct current from a battery) into a "flow" where the electrons wiggle back and forth (alternating current, like what comes out of a wall socket).
First vital question:
Do the sockets on the inverter look exactly like the ones you would plug a lamp into?
If no, things get complicated.
If yes, then you are ok to plug the laptop's plug into the inverter, but don't do that yet.
Many inverters are designed for use in a car to create power for stuff normally used in your house, like lamps and laptops. Is this what you have? Something that came in a box that said something like, "use home applicances in your car"?
If no, things get complicated.
If yes, still not home yet. American cars use 12 volt batteries. Does the tractor battery say "12 volts" on it?
If no, things get complicated.
If yes, the connect the inverter to the battery and wait a few minutes just to be sure nothing gets hot and starts smoking.
Then plug in the laptop and you should be ok.
Now, the whole marine versus tractor versus car battery thing.
Marine batteries are often used to power trolling motors on fishing boats. They are charged at home, taken out on the boat, and run dry, or nearly dry, then taken home and recharged again. This is called "deep cycling".
Car and tractor batteries are made to deliver big power for a short while, long enough to start your car or tractor. If you repeatedly deep cycle a car or tractor battery, it won't last as long as a marine battery will, because it is not designed to be deep cycled.
It will last until you use up all the stored energy, and it will almost certainly allow you to recharge it, but it is not a long term solution.
How long will it last, how many times can you recharge it and keep powering your laptop?
I don't know. A fisherman who ignores manufacturer's recommendations on a regular basis might.
Key decisions, is it an automobile inverter and is it a twelve volt battery?
If yes and yes, and if you know which clip goes to the positive battery terminal and which goes to the negative terminal, hook it up, battery to inverter only, watch it for a minute or two, and if nothing smells funny, plug in the laptop and run with it.
Plan on maybe having to buy a new tractor battery next time you need to start the tractor. You might not need to but plan for worst and hope for the best.
You can get around this with a pair of jumper cables or a couple of wires. The center, metal point of a lighter plug needs to be connected to the + side of a battery. The metal on the sides of the plug connects to the - side. If you have jumper cables, you can clip the red on the center and the black on the sides of the plug, then just connect the other end, red to + on the battery black to -.
If you have any doubts about anything, just plug a lamp in the inverter first, bulbs are cheap.