Joining a new alliance is a lot of work.
First, you have to find out where your corp is going to be basing out of. Then you need to find out the best routes to and from empire for logisitics, because the shortest route is not always the best if hostiles know about it or live there.
For capital logistics, you need to find out where the friendly towers are, jump beacons, jump bridges, POS passwords.
You need to find out and join all the intel channels and make sure you know which are for joining fleets and which are for hostile spotting, and in some cases which intel channels are for which areas of space.
You need to find the link for the forums and register with them. You need to get the address for the voice comms server and get registered there.
You need to get a map of the relevant regions ready and then spend weeks getting to know the system names and who tends to be found where.
You need to read all the alliance evemails, filter out the unimportant ones, and get a feel for who the alliance leadership and fleet commanders are.
Then you need to actually move you entire corp and their required assets to null sec space safely and timely 'cause no one wants to lose a few billion due to a bad frieghter op.
Once all that is done, then you begin the actual effort of integrating into a completely new group of people who don't know you from jack, trying to show them that you and your corp is worth their salt and bring something good to the mix. Its like dating only the end of the date ends not with sex but shooting enemy ships in the face.