First of all, you should make a selection of ambassadors and then it is essential that you communicate the benefits of being part of your ambassador program.
This communication can be through a series of emails and can be accompanied by videos of the first steps in the tool. Also, if possible, it will be interesting to convene ambassadors where you can help them to take their first steps.
On the other hand, before the ambassadors get access to the platform, the Content Library should have a first proposal of content that adds value to their social networks.
In order for them to access the platform for the first time, you can send them an invitation to participate in the program from BeAmbassador itself or by other means such as WhatsApp.