The "Set Next Statement" feature is currently developped and supported. However, the "Edit And Continue" feature isn't just yet. The latter is rather tricky as it requires quite a bit of work and some important changes to Lua in order for it to work.

To use the "Set Next Statement" feature, simply right click in the code at the line you want to set as the next statement to execute and select the "Set Next Statement" menu item. Alternatively you can simply drag and drop the debugging cursor in the gutter (the gray area located in the left side of the edit window of the script you are debugging).

I hope this answers your question.