Flip will list the posts in the opposite order - what is now at the top of the list will be at the bottom and vice versa. Useful for seeing the latest when there is a long conversation. Click on Flip to see it. Click on Customise to see what that does, there are several things you can alter, too many for me to write here.
There are choices in the pink strip above each post too. Add comment is obvious, Report sends a note to Gransnet Headquarters about a nasty post, and Private message lets you reply privately to the member who sent the post below it. You can click on all these to see how they work without immediately committing yourself to anything, so you can explore.