To validate your idea you need to show interest from potential students.

To do that you need to show them something to be interested in. However, a teacher isn't going to go out of their way to create content for a site with no students waiting. To get around this issue, I would start off by getting a bunch of existing content that you can collect and curate on your website. This is how you do that:

Go to YouTube and Instructables (and similar sites), and spend a week searching through videos and instructions, collecting all the best content you can find. Try to get ones that are good, but are not universally recognized already with millions of subscribers/viewers. Then

A) Contact the creators of that content, telling them that you're starting a new website and you'd like to embed their content to attract new students. Tell them that you'll be tracking the popularity of their videos and the most successful teachers will be invited to be instructors on your future (more developed) website, with some special offers (e.g. lower % of their profits go to you). Also tell them that you will not be making any money off of the initial Beta-validation version of the website that you're currently building, it's solely to start attracting students.

B) If as you reach out to these teachers you find a big negative response (e.g. 90% say no and then set their videos to not be embeddable on external sites), then stop telling the teachers, and just use their videos. You won't be doing anything immoral, because you won't be making any money off of your initial Beta-validation website anyway. And when you launch your more developed site you can still reach out to the creators with the most successful videos on your Beta site.

To add some unique added-value to the embedded content, you could maybe even somehow couple your own additional clarifications, etc. with the content, to clarify things you feel they didn't fully explain, etc.

As you start getting students visiting your site and watching videos, make sure to be collecting email addresses so you can do a drip campaign to keep them coming back for content you suggest. As your student visitor # starts increasing you can also slowly start reaching out to teachers (either the ones from YouTube, and others from Udemy, etc.) to get more content created specifically for your site.

If you'd like more detailed advice relevant to your specific ideas I'd be happy to help,

Lee

Before building your online training product you might want to consider simply trying to sell your product. If you can't sell it to at least one business (if a B2B) or to 10 consumers (if a B2C) then you won't be able to sell it to thousands. I'm in the business of helping validate ideas and selling is the best measure. Best of luck and if I can be of help, please connect via my site http://TryHypothesis.com

I think what you face is the proverbial challenge startups run into of how do you demonstrate value without users and how do you get users until you have value.

Online training is a great niche market with the opportunity for huge profits. At the same time its an increasingly crowded market place so you need to really focus on what is going to differentiate your business (see: http://sellyourcourses.com/is-selling-your-courses-a-good-idea/).

If I were you I would focus on content first. If you are willing to invest in taking the trainers material and building an online course out of it and sell it on you platform there isn't a huge down side for the trainers. That process can take a while and be pretty involved so you are offering to do a good amount of work at no cost. In that instance 50/50 seems fair.

Udemy's model works better if the trainer is on the hook for developing all the content since they are doing the leg work - but honestly if the trainer can do all of that there are a lot of different platforms they have at their disposal to sell their content.

In any case I would start with a few key courses and get a minimum viable product online. Don't start by trying to build a huge library. Get a few courses online and see what happens. This will allow you to validate your idea and you will learn a lot based on the feedback you get.