Do not use InDesign for this! None of the outstanding tools that makes InDesign a piece of software for graphic professionals will help you here: advanced typesetting (typographic niceties such as ligatures, real small caps, ), full color management (spot and process color separation), PDF output (crop, bleed, and print marks; PDF/X standard), and general workflow (file templates, master pages, object-, table-, paragraph- and character-styles). All of these tools are worthless to you, and worse than that, they will hinder you.
There are no tutorials to be found because noone would use InDesign for your purpose. InDesign is to create layouts with, for use in the professional printing market.
There is virtually nothing in InDesign that makes it suitable for drawing floor plans, other than that it allows "draw stuff and move it around on the screen". Other, targeted, software is much easier to work with, more accessible, and in general more geared towards doing what you want to do with it
TLDR: do not use InDesign for this! It is like lending Michelangelo's fine brushes and priceless oil paint because you want to paint a door.(*)
(*) And then complain, because it is so inconvenient, what with those tiny brushes and way too oily paint ...