How far can I use someone else's argument in my work?

You are perfectly OK to use their points and take inspiration from the resources you use, provided you do not copy word-for-word or use an historian's argument and pass it off as your own by putting it into your own words. When you see a point or argument you like the sound of, look for other resources/books that agree and disagree with that argument. You will, of course, have to give your own point of view, too. I usually like to do this at the end, so I'll give an example below of a random scenario, just to give you an idea of what I mean.

I don't know what level of study you are at: GCSE? A level? Uni? The below example works for all, but it would help to know what level you are at. I'll choose a GCSE-style / A-level-style Q as my example.

Example Q:
To what extent was Charles I's personality the main cause of the English Civil War?

Example A:
There is evidence to suggest Charles I's personality was a causative factor of the English Civil War. In his study of the king in the early years of his reign, HISTORIAN ONE says "insert quote", which supports the view that Charles's personality led to the breakdown in relations between crown and parliament leading up to 1642. HISTORIAN 2 seconds this argument, saying X, Y and Z (paraphrased). But not all historians agree that Charles's personality was to blame for the outbreak of civil war, with HISTORIAN 3 claiming"insert quote about parliamentary sanctions". It is clear from the evidence that Charles's personality did play a role in the disintegration of communication between the king and his ministers, but it is also clear that a number of other factors contributed to the outbreak of war, predominantly the sanctions of parliament against the monarch. Bla blaa bla....

I've just done this off-the-cuff, but hopefully this gives you an idea of how to argue in an essay. Never pass off historians' words as your own, because you need to show that you understand how to use resources properly and effectively. The last sentence is an example of how I used Historians 1, 2 and 3 to form my own opinion and argument. Obviously, I'd need to flesh it out, but this is how I would do it. This is what I did for my GCSEs, A levels, and even my degrees, so it's a solid format that gives structure to your argument(s).

To recap:
1. Use other historians and their words to inspire you own argument, but always reference them when you quote
2. If you are just paraphrasing an historian, as I did with Historian 2 in the above example, still footnote/reference them. I'm not sure what referencing style your school asks for, but always reference a quote and always reference when you paraphrase, because you still used that historians' work even if you didn't directly quote them
3. The last sentence is where you can use the above evidence of Historians 1, 2 and 3 to create a concluding argument of your own. At the end of the day, all historians form their opinions based on the research of other historians. So you use the evidence at hand to form your own opinion/argument and then flesh out that argument and back it up with yet more evidence.

I also want to point out that the first sentence in my example 'There is evidence to suggest Charles I's personality was a causative factor of the English Civil War' is a sign-post sentence, and if you haven't studied those in school then you should spend some time Googling or ask your teacher to go over this with you. It makes essay-writing so much easier, because it lets you - and the reader - know exactly what that paragraph is going to be about. In this case, the personality of Charles I. It will always get you some good marks when it comes to layout and structure.

I really hope this helps and hasn't just confused you even more! Let me know if you need me to clarify anything.