I'm glad your first session went well. It can be intense, but also such an important part of healing.

As for how to participate, definitely dig into some of the stickies at the top of this board, e.g.
Survivor to Thriver and
How to Get the Most Out of This Site.
I would suggest sharing your story as you are comfortable, asking for help with problem-solving, and reading and commenting on others' posts. It all helps work toward healing and growth. I've had some of my biggest growth and a-ha moments here in noticing how members talk to each other, work through the process of establishing healthier boundaries, and practice skills like validation in responding to one another--those are skills that those of us who are children of BPD parents didn't have modeled for us.