In charge of a defense that finished last in the NBA in too many categories last season, Timberwolves interim coach Sam Mitchell has stepped backward in order to move forward.

Back to long training-camp practices in which his team went nearly two hours with barely touching a ball to start Tuesday’s first practice.

Back to the basics, such as starting with something as simple as the defensive stance and beginning to install a system intent to strengthen their defense from the perimeter on in.

“We know we have to get better defensively, and the only way you’re going to get better is to work on it,” Mitchell said. “We understood at the end of last season that we just have to get better at it. The players understand that, the coaches understand that. You have to work at it and try to get better every day.”

The Wolves have accomplished veteran defenders Kevin Garnett and Tayshaun Prince. They also have eight players on their roster who are 24 years old or younger. Included are five who played just one collegiate season.

“We started with the very basics, and that’s what you have to do sometimes, especially today with young players,” Mitchell said. “Most of these guys had one year of college. They play AAU ball, but it’s not like when I played high-school and college ball and we just got drilled and drilled and drilled on stance and sliding and turns, all that stuff. We just felt we had to start our defense with the stance and get back to basics.”

A veteran such as Prince — four times named to the NBA’s all-defensive second team in his younger years — can’t remember revisiting something as remedial as the basic defensive stance since he played for Lawrence Frank in Detroit four seasons ago.

“I haven’t done that for a while,” Prince said. “In Memphis, we had a very veteran team, so we spent 20, 30 minutes on defense, did a couple ‘show’ drills and stuff like that and went on offense … Sam threw into everybody’s ear what the defensive percentages were last year, last in the league. So the most important thing is putting it in our ear right away and letting guys know.”

Lacking a single true shot blocker not that many years ago, this season’s Wolves have not just one, but potentially three or four who can alter or block shots with centers Gorgui Dieng and Karl-Anthony Towns as well as Garnett and second-year forward Adreian Payne.

Mitchell, though, wants his team to improve their on-ball defense — hence the defensive-stance work — enough that it doesn’t have to rely on that last line of defenders.

“We have three or four guys who can do that, but if we’re constantly protecting the rim then we’re not doing a good job defensively, right?” he asked. “Hopefully, we do a better job so our guys don’t have to protect the rim on a consistent basis. Hopefully they’re rebounding and outletting the ball and getting down the court. If they’re protecting the rim all the time, that means people are penetrating our defense too much.”

Mitchell intends to utilize the Wolves’ young legs and the athleticism of young players such as Andrew Wiggins and Zach LaVine to build a more aggressive defense that can stop the ball before opponents can get into the paint and to the basket.

“They’re athletic, they can defend and they can play a lot of spots,” Wolves point guard Ricky Rubio said of his team’s youth. ‘‘Defense is what wins games, win championships. We want to build from there. I know we have a lot of talent, and we can score a lot of points. But we have to start with our defense. That’s going to be our base. The veterans, they’re very good. They can help in guiding the young guys how to do it.”

Scrimmage time

Some tickets remain for the Wolves’ open scrimmage Monday night at Target Center. Tickets are free but must be reserved using a credit card in advance on timberwolves.com. The Wolves open their seven-game preseason schedule Wednesday against Oklahoma City.

Asked what he wants to see Monday, Mitchell said, “Just execute the things we’ve been doing: Get up and down the court, play with spacing, play with flow, move the ball, make hard cuts, set good screens. The same things every coach wants to see. Let’s see if they have gotten better the five days we’ve been practicing.”