In early stage, there's no sales. There's talking to customers and solving their problems. Sales comes after product-market fit.

What would you call the attracting of the initial customers?

I'll first answer in idealized terms. These initial customers should be early adopters. Early adopters don't need to be convinced. They would jump board, because you are offering a solution they have been looking forward to finding.

This is a very romanticized view of starting a business. And, IMHO, this is a formula to build businesses that appeal to VCs. In reality, starting a business begins with listening to potential partners. I don't like to call them customers, because they are not, at this stage. One should test if there are common problems. Validate that these are worth solving. Develop an MVP. Rinse and repeat.

Market research or product fit

validation? proof that there are people who actually want to use your product?

Customer development

Find leads, market your products to them, set low expectations for yourself, listen to their feedback, close the deal, support and retain the customer.

Sorry but this sounds like "now draw the rest of the owl" to me... How do you find leads? How do you market products to them? How do you get them to say a word of feedback? How do you close the deal? How do you retain the customer?

I am trying hard for the past decade but all of these still go right around my head.

> I am trying hard for the past decade but all of these still go right around my head.

What have you tried so far? There is plenty of information available (even in these comments) about how to find customers.

> sales people would try and take a substantial clip of any ongoing business

As others have said here, take this as an opportunity to learn something new and add sales skills to your toolbox! At a certain point, though, you have to reckon with the fact that paying for sales is better than making $0.