The South African-born duo will link up with the Warriors in late November after completing their studies at Kingswood College in Makhanda, having officially agreed terms with the club earlier this summer.
Scottish-qualified through their grandparents, the twins are already familiar with the Glasgow environment after spending time with the squad during the club's trip to the southern hemisphere in April.
They also previously spent time in Scotland as pupils at Glenalmond College, with Ryan revealing that Scottish Rugby figures Kenny Murray, Alastair Kellock and David Nucifora all played key roles in bringing the pair into the Warriors pathway.
"That process was well underway before I got here," confirmed Ryan. "Kenny Murray, Al Kellock and David Nucifora were all heavily involved. My understanding was that they were identified through the Scottish-qualified programme.
"They spent a bit of time here, and I think they went to school here at Glenalmond for a few terms, so they'd already had a few touchpoints with the environment here. All of that was done prior to me coming in January.
"Once I arrived, though, I obviously got to know the young men a bit better, and we worked through the process towards the middle of last year to finalise everything.
"They're very exciting athletes with really good potential, but we've also been very clear with them that, once they get here, it's a bit of a clean slate. I can say from first-hand experience that joining a club mid-season isn't easy.
"From that point of view, they're very aware that they've got to earn their opportunity within this environment and within the Scotland pathway generally.
"We don't want to create a culture where people can cut corners and get opportunities before they've earned them. They certainly understand that, and the staff and I have been very clear about it.
"That said, we're really excited to add two young men who've got good character, as well as some very good athletic potential."
Despite the pair not arriving at Scotstoun until the season is already underway, Ryan says preparations are well advanced to ensure they can hit the ground running.
On them joining in late November, Ryan added: 'Although they'll miss the first part of the season, the club, Luke (O'Dea) and I have been in pretty constant dialogue with them around their strength and conditioning, and making sure they're reasonably across what we're doing here day to day.
"We've already inducted them into the environment remotely, so they've got a good sense of what the club is about and the programme they're joining."