Hello there Lamna, first thing you need to to is to set up a "masquerade", there should be an option for it on the left side of the bar (named persona i'm told). Once you have done that you should go up to the top bar, select "groups" and then find the Thayan enclave. Click "request membership", and be sure to be logged in on your masquerade as you do so, so to sum it up:

1) Create persona for "Niirfa-samm Willennesen"
2) Switch to the masquerade (persona) "Niirfa-samm Willennesen"
3) select groups.
4) Select "request membership".

Then once Akhalia has had time you will be added to the group, hope this helps!

edit:
Clarified the post to help a bit, thank you for the critism TwoCats