Bath's new head of rugby Johann van Graan said a "whole journey" needs to be undertaken at the club after they finished bottom of the Premiership.
The club won five league games last term, recording a worst finish since the professional era began in 1997.
They endured a torrid first half of the campaign and lost 12 consecutive matches in all competitions.
Former Munster head coach Van Graan was appointed in December but only started in the role on July 11.
"When you come into something new and you change everything it doesn't just happen in week one," Van Graan told BBC Radio Bristol.
"We've changed our whole calling system, we've changed the way that Bath have operated before because I believe that we needed that change of direction and that's going to take time to bed in."
The South African was made head of rugby in a coaching reshuffle in May, with former director of rugby Stuart Hooper becoming the team's general manager.
JP Ferreira followed Van Graan from Munster to take up the defence coach role, while incoming former Bath wing Joe Maddock was made attack coach.
Bath open the new campaign with an away fixture against west country rivals Bristol on September 9.
"I said to the group, we all start from zero. What's happened has happened in the past and we'll take our learnings from the past, but from my point of view all the players are on zero.
"It's a new squad of players, a new whole support staff in terms of medical, athletic performance, coaching, nutrition, operations and it's what we do now that will determine the future.
"I'm under no illusions that there is a whole journey to be undertaken here. We start from a position that we need to work ourselves up and the people are excited, the playing group are hungry and we are going to learn and grow together because we will need a lot of growth in the coming weeks, the coming months, to make sure that we perform on the pitch."
A long-term vision for Bath
Van Graan spent five years with Munster and led them to two European Champions Cup semi-finals and the 2020-21 Pro14 final.
He was South Africa's forwards coach when they reached the semi-finals of the 2015 World Cup and was part of the coaching team that saw the Pretoria-based Bulls win the Super Rugby titles in 2007, 2009 and 2010.
The deal with Bath saw him sign a "long-term" contract.
Bath have won the top flight title six times, most recently in 1996, and they have reached the league play-offs twice in the past decade.
"Our main aim will be to give ourselves small goals to start with and try and reach them week by week but the bigger picture is a vision, where are we going, where do we want to go," Van Graan said.
"That's pretty clear in my head but it's not about me, it's about the club of Bath. You need buy-in from everybody.
"You need buy-in from the board, from supporters, from staff, from players and we've got make sure we're all pulling in the same direction and hopefully we can start generating some momentum through the months and years to come to get Bath back at a place where I believe it should be."
Last season Bath conceded 763 points - the second worst in the Premiership - and scored 57 tries which was also the joint lowest. Among their losses was a record 71-17 defeat to Saracens and a 64-0 thrashing by Gloucester.
"We've got to improve our performance on the pitch. The first thing that I said to the group we've got to become tough to beat," Van Grann continued.
"It's no good to talk about all the nice things, we've got to go and work on the training field, work hard on our habits, embrace change because there'll be a lot of change.
"And then a rugby game is a collision sport so we've got to improve our contact, we've got to spend time on our set-piece, particularly our maul, we've got to make sure that we improve our defence dramatically and then finish our opportunities and what we create in attack.
"It won't be perfect in week one, it might not be perfect in year one but there has to be a progression in terms of our performance on the pitch."
As well as areas on the pitch, Van Grann pointed to Bath's medical and strength and conditioning as an area that needs improvement. At one period last season, half of the club's first-team players were unavailable with injury.
"Medically speaking we've got a very high rate of injury and re-injury. Rory Murray [new head of medical services] is somebody that I believe can make a difference," Van Grann added.
"We're a team that need to get fitter and improve our performance under pressure. Last year this was a team that conceded a lot of points in the last 20 minutes in some terrific positions and they let the game slip."
Namibia prop Aranos Coetzee has already been brought in to the team as injury cover ahead of next season, but Van Grann said more players are required going forward in the short and long-term.
"I'll take my time in assessing where I think this group needs to grow and where we need to add," he said.