Before installing Aiakos you have a number of things to consider.
You need to decide what fields are captured on registration, which are mandatory and which are optional. You will also need to decide on syntactic and indexing requirements for the fields. Once you are clear on this, you will need to assemble an LDAP schema. Some tools will be provided to manage this (although they aren't yet).
The registration screens are multipage forms. The current forms are based on our schema, which is probably not what you want to use. Some tools are provided to build new forms for you, although these tools are currently pretty rough and ready.
If you have existing user databases, you will need to merge these into your LDAP directory. There are many potential gotchas involved in this, especially if you have multiple disparate databases.
Aiakos Server Toolto your portal. This will also install and configure acl_users, portal_membership and portal_memberdata supplied by LDAPUserFolder and CMFLDAP. You will need to provide the details for your ldap server.