In this instance I’d rely on cold calling. Physically go and meet companies you’d like to work with. Offer them a novel programme that’s of value to their employees or customers and is a little different from other options but not too quirky that it wouldn’t be difficult to share. Employers endorse you when they hire you so they need something non contentious.
If you have no existing testimonials behind you and are really in a start up stage, you may need to offer a discount eg 75% savings on the programme for the first 5 clients or for the first 3 sessions.
In my trips I discounted the “Pilot Programme” to get the client names and testimonials to endorse me going forward and test my product/service. Piloting a programme also removes the risk to the client as they are under no illusion that you are a start up and they get to share in this experience.
Once you have some names and testimonials the other forums of marketing are a little more effective but in my experience…it often comes down to cold calling and eventually word of mouth.