Hi! When is the NArGS seed trading and plant sale stuff?

Also, any tips on germinating alpine flower seeds?

NARGS has a seed exchange to order from. There is no trading. You must be a paid member of NARGS, not your local chapter. The first round of ordering is over for this year, and the surplus round begins late March.
https://www.nargs.org/2020-onl...

Also, any tips on germinating alpine flower seeds?
This is a massive question. Start here:
https://tomclothier.hort.net/p...

And here:
The thread "The Ultimate Resource for Seed Collectors" in Seeds forum

If you want to grow alpines ,then you want to join NARGS.
There is a large treasure trove of information there.
The seed exchange is fun and you can get some neat alpines from it.
It is for members only. We send seeds in the fall, and they are usually distributed in January except this year.....Covid made it later.
Then there is a second offering of the surplus seeds in March.