Ok so the cheat path can start on Day 1 but it is really anytime before Jamie gives you the ok to be with other girls. Day 1 you have the option to cheat on Jamie (as of the current release there are no consequences for cheating on Jamie) you have 3 times total you can cheat on Day 1, the first one is to agree to have a secret relationship with Shauna when she spies on you in the shower (it will lead to sex later that day). The second is to agree to have casual sex with Racheal when you go to pick up Azel at work (doing this will open up her lewd business opportunity that starts on day 2). If you have sex with Rachael on day one you will also get an option to have sex with Alexis in the bathroom after dinner with Azel. There are additional options on day 2 with Elizabeth, as well as Anna (client of Racheal's), Day 3 has an option to mess around with Katie prior to the ok with Jamie.
The no cheat path is basically don't cheat on Jamie until after Day 3 pool scene where she gives you the ok to mess around with other girls. You get a lot less early content going this route and lose the opportunity with a few girls {Alexis, Anna, Brittany, and Keyana} as well (this may change in the future, with the week 1 re-work).
Most people seem to go cheat path, not everyone picks every girl to be added to the harem either. The guide is meant to show you how to get the girls you may want to add to your harem and not a step by step path. To my knowledge there is no wrong way to have the girls added to the harem. Trust me by the time you get through day 8 you learn how excited Jamie and Shauna are to hear about you with other girls and see you with them as well. This game is a lot different than other Harem VN's which is why I enjoy it so much. At this point there seems to be no right or wrong way to add characters to your harem, some will live with you and some will just come by to hang out with you. Either way I hope you have fun with the game, try out a lot of the options and join us for chats about the game here.