We learned a ton from the first episode of HBO’s “Hard Knocks,” which debuted Tuesday night.

Mostly, we learned about the use of expletives and absorbed financial advice in addition to getting our first glimpse at whether the Cleveland Browns, who have won one game over the past two seasons, will be any good. What we mostly took away is the knowledge that Jarvis Landry, who was traded to the Browns in March and signed a five-year, $75-million contract, ain’t messin’ around. He called out his brah-thren big time, challenging them to eschew the ennui of their old ways. And it’s HBO, so the f-bombs were flyin’.

“I don’t know what the [expletive] has been going on here, and I don’t know why it’s been going on here, but this — if you’re not hurt, like if your hamstring ain’t falling off the [expletive] bone, if your leg ain’t broke, I don’t know, you should be [expletive] practicin’. Like straight up,” he said. (Watch the unbleeped video; send the kiddos on an errand.) “That [expletive] is weakness. That [expletive] is contagious as [expletive], and that [expletive] ain’t going to be in this room, brah. That [expletive] has been here in the past and that’s why the past has been like it is, brah. That [expletive] is over with, brah.

“If you are going to [expletive] practice, [expletive] practice. You can’t get no better. Ain’t nobody going to get better by being on the [expletive] sideline if you ain’t [expletive] hurt. If you’re not [expletive] hurt, you’ve got to [expletive] practice because you make other [expletives] work even [expletive] harder and they’re more at [expletive] risk of gettin’ hurt because you’re the one [expletive] practicin’ because you’re bein’ a b—-.  Straight up, that [expletive] is [expletive] real, brah. That [expletive] ain’t happenin’ here. I’m just lettin’ you all know. That [expletive] ain’t [expletive] happenin’ here.”

He wasn’t finished.

“I ain’t taking no [expletive] days off because I can’t be [expletive] great that way. That has to be the attitude and mentality all the [expletive] time. All that weak [expletive] don’t [expletive] live here no more. That [expletive] don’t exist. It’s contagious, brah. It’s really [expletive] contagious. It’s contagious.”

To recap: It sounds like some guy named Brah is really in for it; somewhere in Bristol, Rex “Let’s go get a [bleep] snack” Ryan weeps; and, for $75 million, you get a real freakin’, frackin’, flippin’ locker-room leader who, in about 90 seconds, manages to drop 32 or so expletives of varying degrees (but mostly of one degree).

More helpful was the financial advice dispensed by defensive lineman Carl Nassib, a biology major at Penn State. “You can make billions of dollars!” players were told. You can double your money every seven years following the Nassib method and also possibly meet Taylor Swift.

“All we got to do is put $100,000 in the bank and let it sit there?” he is asked.

“It’s called interest and it’s so [expletive] easy.”

Practice and compound interest. Week 1 was gold.

Read more from The Post: