As those are both community contributed projects - and not official Camunda products - we don’t have any videos or tutorials on using or extending those. If you search around there are some community contributed tutorials on building a custom Tasklist application using the Tasklist API’s. The APIs are open, so you can implement it in whatever language you prefer.
I did a quick Google search for “camunda 8 custom tasklist” and found lots of great information. Here’s one video about implementing just the UI in React; this user who built a custom Tasklist with Vue.js; as well as many threads in this forum with users asking questions about implementing their own Tasklist.