What I'm going to do in this guide is explain the strategy that I follow when I open a park in challenge mode on hard difficulty. There's no telling if this works on Harder, but it might, so feel free to try it out.

Starting Up
Just start up with any area you feel like. When the land loads, keep in mind that you only have $2,000 to start with, so coasters are basically out of the question for now. Depending on which land you chose, you may or may not have a path to start out with; if you don't, take care of that before moving on (Don't spend too much on it). In the flat rides menu, you should only have the Venetian Carousel ($1,200) and the Wild Blue ($1,600). Most people would instinctively go for the Venetian Carousel because it's cheaper. I'm here to tell you that you shouldn't do that. Since the carousel has a very low excitement rating, it won't attract very many people, and you'll lose money very quickly. So, start with the Wild Blue; it has a much higher excitement rating, and it will attract more people. Build it close to the starting path and do all of the necessary steps to allow access to opening the ride, like building the entrance and connecting it to the main path via a queue line. When it comes to building the queue line, build it so it's short enough for guests to want to wait in but long enough to the point where you can decorate it; trust me when I say that it's incredibly difficult to decorate an incredibly short queue path. Decorate the queue until the scenery rating gets up to about 30%, set the ticket price to $13, and then open the ride. Now, feel free to fast forward and wait until you get around $1,000.

Rides Breaking Down
Since you're playing on hard mode, rides will break down very often, which can seriously mess with your ability to make money. So, you have two choices; you can either just be normal and hire a mechanic to do the work, or you can be like me and use cheats. For those of you who do not know, Planet Coaster has built in cheat codes that do various things throughout the park, but the one I'm going to focus on is "Frontier." If you rename a ride "Frontier", it will stop ALL rides from breaking down, even in challenge mode. Trust me when I say that it'll save you a lot of money if you decide to go with it.

Food and Facilities
Now that you have $1,000 or more, you should really consider placing food shops down. Expand the main pathway to accommodate a Chief Beef Burger Shop and Cosmic Cow Milkshake Store (You can also build a building around these two shops; while it's not necessary, it'll come in handy later). Adjust the prices to be $1 more expensive, and open up both shops. Now, pause the game. Place trash bins down absolutely everywhere. Unpause the game now. Both shops should attract people immediately and these people will complain about needing the toilet, so place a toilet block. I don't strictly advise against charging to use the restroom, but if you're going to charge, keep it $.10 or lower. Once you step above that threshold, people won't want to pay for the restroom anymore. Also, because those trash bins are starting to fill up, hire a janitor. Feel free to kick back and wait until you get your money back to around $1,500.

Second Ride
When you have your money to around $1,500, you can start thinking about placing down the second ride. This is where that Venetian Carousel comes into play. Build one, and go through the necessary steps. Since you have some more money, you have a bit more leeway to make the queue longer. If you decided to build a building around your shops, feel free to position your queue so it's right up against the building, as this will help with your queue scenery quite a bit. Now decorate the queue until it's up to around 40% if it's not there already. It won't make waves right away, but it will attract family groups, which will be willing to spend money to ride it.

Researching a Third
Now that both flat rides are down in the park, you'll have to research the third one. Go to the research menu and choose a flat ride to research. When thinking about research costs, think about researching at the lowest rate possible; an entire ride will only cost around $1,500 to research but it will take some time. Allocate the amount of money you want, and then close the menu. While you wait for this to research, feel free to place random bits of scenery around your park to boost the park rating. When it finishes researching, save up the amount of money it costs to build, build.