Warm them up with a hairdresser the use a knife to get a corner up.
Hopefully the glue strength is less then the screed strength so the scredd stays down.
Cant use the 1st one. Thats for glue down. You need an expansion gap. Need the 2nd one. Look on stairs rods website.
https://stairrods.co.uk/ali-top-nose
T&G is the best locking system imo. No creaking which you can get with some click woods.
You need to glue each side and use ratchet clamps to hold it all together while the glue sets.
Get a good underlay. We use Timbermate excel.