Here you can read all about the practice and sign up for a free, online retreat:

https://www.dhammasukha.org/

You can find a lot of dhammatalks, info and faq here:

https://www.suttavada.foundation/

Delson has his own website now, with info about physical retreats:

https://delsonarmstrong.info/

A group where meditators, guides, and monastics discuss the practice:

https://groups.io/g/dhammasukha