“It’s not about ideas. It’s about making ideas happen.”
Who said it: Scott Belsky, co-founder of Behance
“It’s about” is a way to highlight the importance of something. For example, “It’s about doing a good job” means what’s important is to do a good job.
“Make it happen” is an expression that means to get things done or to do the work. For example, “If you want to get a promotion, then just make it happen” means if getting a promotion is your goal, then you must work now to get a promotion.
The full quote means that ideas themselves are not important. The important thing is that you take action so that the ideas actually come true.