To make an alliance go to pack>pack activities>manage alliance
Set the name, description, etc. and submit
To set a specialization go to pack>pack activities>specializations and select the one you want. They're described there.
Only one can be used at a time, so if you change it you won't get the bonus of the specialization you last had
(I don't believe you completely loose the progress, but you don't get the bonus from any specialization unless it's what is selected as your active specialization)
The play option can be used after each successful explore session. Once you've completed the session successfully go to the pages of the wolves you brought to that explore trip and click one of the choices that are unlocked(it will be colored, not a faded picture)
Once your wolf has played successfully 25 times you can trade those play points in for 25 CP