I'm a technical co-founder of 2 products.
RetroNet and ShareFinder.
One ran out of cash it raised and is in limbo. It generates some revenue from sales of hardware that we developed , but not what we hoped for. The other is doing fairly well so far.
Over the course of about 12 years in the software industry , I've received about 25 inquiries into this very thing. Some have been requests to work for equity only , equity + cash and combinations of other incentives. I've accepted about 1.5 of these 25. I would have loved to have done others. But theres only so much you can do with one lifetime , so you pick the best ones you can and move with them.
The above advice given by others is pretty solid. My go to plan for something new would probably be something like (and to echo some of the above):
1. Do market validation and research. Talk to many potential customers about your idea.
2. Do mockups of how the interface would look before you do this. Don't code anything for the moment. There are many apps and tools which allow you to "make" software that doesn't actually work , but gives you a good idea of how it would work. Use one of these tools and iterate through them with customers.
3. Try and estimate how long it would take and how much it would cost to make a product that contains the minimum number of features that people would actually use and pay for.
Break down each component and try to get a cost per hour. Here are some actual dev salaries to help
OfferZen flips the normal recruitment model around, so instead of applying for jobs, companies send you interview requests with upfront salary.
www.offerzen.com
As a layman , you are going to be many times off the number you come up with. Do not make the mistake of thinking your cost and time estimations will be met. They WONT. Software business don't work by controlling costs. They work by expanding revenue to meet whatever costs are needed.
4. If you are going the co-founder route , have your business together before you start. You need to answer the question of "what do I bring to the table" in a brutally honest way. From industry standards , your idea is roughly equal to what a royalty commission would be. In the tech industry thats 5-10% . That means your idea gets you 5% of the company initially. That's it. The rest is up for grabs. You don't get 50% for an idea. How will you determine how much to give yourself and the tech co-founder?
I like the Slicing pie model to distribute equity.
. I have seen a number of projects fall apart because the technical co-founder wasn't offered proper amounts of equity. In a lot of cases , the technical co-founder is more valuable than the non technical one and therefore gets more equity. You may need to adjust your mindset to be comfortable with this. Don't just try split the business 50/50. Even if the co-founder agrees up front , resentment will set in if their offer isn't fair.
And as others have mentioned : DONT start with a junior developer. You will regret it. If you can't get someone to start with that's fairly senior , don't start. I would say 3-4 yrs experience minimum.
5. Go to a software company and ask if you can work in their environment to learn , even if its for free. You cannot simply rely on the technical cofounder , and there is a lot of understanding of the software world that goes into being a startup CEO
Do all this while still working your day job. Try a slow burn approach for the first 6 months. Don't rush to go all in all at once.