using blog settings >> comments , you can

Control comments Received by your blog visitors
if you want to give the ability for everyone to visit your blog and make a comment just select Anyone , as you can see below ..



but if you want to receive comments from bloggers only , select only bloggers and save your changes ..

by defualt, comments received from blog visitors appear on the blog by minutes , you can stop Receiving comments from visitors by select the Comments hide option .

Control comment notification
if you want to receive an email when someone post a comments on your blog just check Email me when someone leaves a comment on my blog .

The final option gives you the ability to control the appearance location of comments.

Using show comments in the same page ?option you can :

Check (Yes) if you want the comments to appear on the same page

Check (no) if you want the comments to appear on a different page