Our intros have all been done the same way mostly. The biggest change being sometimes we have rushed a bit. but my wife has got them all together just fine.
We started with 2 gliders with 2.
then we added 2 to 4. Then 2 added to 6.
We had one failure going from I think 7 and adding 3. We had one female of the 3 that was chased into the corner of cage at night by several gliders, so ended up removing her after several nights.
this last one we added one to a colony of 4. they are doing great together.
Just follow the instructions. and see how they are reacting.
Most gliders in my experience love to have company, they just need the proper scent training so introductions are done and the glider is smelling a familiar not a total stranger.