Yes because it is a new paragraph.
Yes, you indent each new paragraph.
Horizontal Ruler
Certainly, so long as the rest of the paragraph pertains to the dialogue. You can describe the character's actions and thoughts. Once you move on to another character, though, you need a new paragraph.
Hanging Indent
yes you should because it is the beginning
No, you do not have to indent each time someone speaks in a dialogue. You can simply start a new line with the speaker's name or dialogue tag to indicate a change in speaker. Indenting is one way to organize dialogue but not mandatory.
Yes, in MLA formatting, you should indent the first paragraph of your essay.
An indentation should be exactly five spaces.
No... you just have to indent a paragraph once. If you need a tip just take your finger next to the line that you have to indent and that should be the amount of space that you indented.
Yes.
Yes, Dialogue should be like a conversation. It needs pauses and punctuation, so in each time the speaker changes you start a new line and indent.
Please indent your paragraphs. The bay indents the coastline.