Celtic finished 11th in the Absa Premiership in 2015/16, with Letsoaka effectively swapping jobs with current Golden Arrows coach Clinton Larsen midway through the campaign.
Jampies, who played for Jomo Cosmos last term, is encouraged by the set-up at Phunya Sele Sele.
"The set-up reminds me of that at Ikamva (Ajax Cape Town); professional and well orchestrated development structures that show the seriousness of the team about its future," Jampies told the club's website.
Asked if Letsoaka has outlined his plans to the players, Jampies said: "Partly so, but hey, we have such a knowledgeable, passionate and futuristic mentor who always emphasises on the significance of committing oneself for the benefit of the team. Together with his technical team, they have vast experience that will make us prosper."
Meanwhile, the left-back is hoping to get amongst the goals for Siwelele.
"As you can see, I have already started with extra personal training. The playing system here at Celtic will require a lot of energy and commitment. As much as I’m a defender, I also want to help the team by scoring goals; hence I am practicing free-kicks."