Long-time All Blacks Sevens coach Tietjens has been appointed Manu sevens coach for the next four years but won't formally take charge until the Wellington tournament in January.
Betham, who led Samoa to the 2010 World Series title, led the team at last week's Oceania Sevens in Suva and will be in charge for the opening two legs of the World Series in Dubai and Cape Town next month.
Betham spent three years in charge of the Samoa sevens team between 2009 and 2012, before guiding Manu Samoa to the 2015 Rugby World Cup.
He resigned after the Manu failed to reach the knockout rounds, following defeats against South Africa, Japan and Scotland in pool play, and said he was grateful for another chance to coach on the international stage.
"Just being back has been an honour and a privilege just to be involved again. There's a bunch of new faces, I guess what we're trying to do at the moment is establish ourselves a good foundation base and we will work from there," he said.
"Everything is going to plan at the moment and we're slowly just trying to get into things.
"I've learnt a lot from Manu Samoa fifteens. It's given me a lot more insight in the way professionalism in rugby has gone.
"Just working with most of the professional coaches in Manu Samoa has given me a lot more to think about as a sevens coach.
"As I was the coach before and I didn't get a lot of professional help, everything was done by book and on-island, but now I guess it's a very valuable experience for me coming from fifteens, getting that experience and just trying to be put it together now and help Sir Gordon with what we need to do to move Samoan rugby forward."
Stephen Betham spent three years as a rival to Sir Gordon Tietjens on the World Sevens Series but said the two are enjoying being on the same team.
"It's been great. He's got a lot of new ideas he's come up with and not just the players but me as a coach is I'm looking at learning - if there's anyone you want to learn off it's probably Titch," he said.
"He's been there for 22 years with New Zealand and he's won almost as many cups as years he's been coaching so it's going to be a very good four years for us as we look forward, we've just got to work together.
"It's not a quick-fix, it's not an easy-fix but we've got some plans in place and we're going to try to make sure we implement those plans.
"It's very unfortunate that the way rugby goes is for us coaches it's not the process, it's mainly the outcome now and if the outcome doesn't come out right we could be gone by the end of next year."
A number of new faces are in line to make their World Sevens Series debut for Samoa next month.
The Manu finished runners-up in the Oceania Sevens men's competition at the weekend, beaten 28-19 by Olympic and World Series champions Fiji in the final.
Stephen Betham said about 10 players who featured on last year's World Series are currently a part of their extended training squad but there is also a number of fresh call-ups.
"We took probably seven new faces (to the Oceania Championships) and it was a chance for them to put their hands up. We wanted to measure some of these players - whether they were worthy enough of making that next step up - and some of them answered the call and some of them are in real contention now for Dubai," he said.
The first World Series squad should be announced sometime next week.