You don’t necessarily want a patent.
If you have a great idea, you can just start practicing it yourself. If other people can copy it by looking at it, they may, but you have a business advantage by starting earlier.
If you just start practicing it yourself, and people can’t tell what your idea is by looking at the product (for example if your invention concerns how you make the thing), you can enjoy exclusivity for as long as you keep your idea a trade secret and nobody else thinks of it. However, if either of these things happen, you have no more exclusivity.
If you do patent your idea, you have 20 years during which you are allowed a coercive monopoly and the courts are expected to back you up in suing infringers. However, you have to teach the public the best version of your idea at the time you file, and after the 20 years are up everybody gets to practice your idea as you taught them to.
If you patent your idea, and it concerns how the product is made, and it’s impossible to tell if the product was made with your idea or with some other process, you have just made a bad mistake, because people infringing your patent do so in the privacy of their own facility and you can’t tell they’re infringing. You have no way to start to protect your patent. Patents that concern how a thing is made, rather than the thing itself, are called “process patents” and they are hard to enforce for this reason.
Last point - you don’t have to make a model of your invention. In fact, the Patent Office will not even do much work to figure out whether your invention works. You can often get a patent for something that, it turns out, doesn’t actually work. Such patents are not worth anything if it’s clear they don’t work, though.
So, if you want to go the patent route, you want to hire a patent attorney. like danceswithcats said.