Hi forum

I'm looking to buy a 10" dob (maybe the Mead lightbridge). Can someone explain the "Four-Reticle Red Dot Viewfinder" and how it works. I'm familiar with a typical finder scope, as at the moment I have a small 4" reflector.
All pictures of the scope I'v looked at do not show any finder.
What do you look through ?
Having trouble deciding between solid tube or collapsible.
Any info/advice would be appreciated.
Thanks
Richard