'explains about how' is correct and usable in written English.
You can use it when you want to describe how something works or to provide an explanation of something. For example, "The professor explains about how the law works in this situation."
"We used every technique imaginable!" Baxter explains about how they captured the spectacular visuals.
There's always the question, Warren explains, about how you save the top -- in this case, the public pays for the banks' guarantees and the top executives benefit.
"The original idea came from when my husband and I were talking about food trucks," Collins explains, "about how the food truck thing had gotten really big, and he said well, what about a music truck?
"There's plenty of them to explain about how they're going to remain a relevant player in the smartphone market," said Nick Dillon, an analyst with Ovum in London.
In this section, we explain about how we discover human behavior based on their data and building the human behavior model.
"We, from the beginning, have looked at video as a form of communication," Raichyk explained about how Keek's vision of what mobile video sharing means differs from the rest of the field.
Then we asked if they'd pay $25 and that seemed to spark their interest," Jukely co-founder Bora Celik explained about how his team came up with the subscription concerts price to a crowded room at the SF Music Tech Conference.
Moreover, it has been suggested that it offers a possible way to escape the explanatory gap: If some mental state just is some physical state, then there is nothing to be explained about how "these states" connect; it is a sheer misunderstanding to ask for more than just the identity-statement.
I spent ten minutes explaining about how the car I'd had through Wells Fargo had been totaled.
"At one moment, she stopped everything and explained about how she found out about Embrace after reading about Storm and her son in [HuffPost Weird News]," he said.
"I thought he did a very good job (explaining) about how he reformed the Pentagon, eliminated some weapons systems that were wasteful... (and) basically impressed upon us that the sequestration that we are about to enter is just devastating to long-term planning and readiness," Graham said.
