The roller coaster you start with is the first step towards your objective, but before you can start building the other nine coasters, you will need a lot of money to do so.
Start by closing the transport coaster and cut off some paths, so you reduce the park to about a third for now. Use the pincers to move guests near the entrance and then start building rides and stalls. You will need some compact coasters like Shuttle Loop and Rodent coasters and other rides to complement them. Be sure to place enough stalls, since there long ways to walk, and hire plenty of handymen and mechanics with assigned routes. If you run out of money doing that, consider tearing down the transport coaster. As long as it's closed, it doesn't earn money anyways and it will net a nice sum. On the other hand, though, it's nice to have it once you use the whole area.
The path system basically works, but it will need some corrections so your guests don't get lost and don't walk too much. There are a lot of paths going down and directly back up. Replace some of them by bridges because climbing makes your guests tired. Also, be sure to place a "No Entry" sign at every ride exit, otherwise guests who are leaving the park might turn around at them and get lost. Also avoid dead ends, especially facing the entrance, when adding paths. This way, you should be able to prevent guests from getting lost. If you still have problems with that, observe guests who are lost to see where they take the wrong turn, then fix that. This can be tedious because of the placement of the entrance, but it surely is doable.
After you have a basic park running in the part you cut off, it's time to reconnect the rest of the park. But before that, the transport coaster needs some fixing. It has a lot of kinks and bumps which increase the Intensity and Nausea rating, so flatten the track a bit to make the ride smoother (see picture for example).
Unless the ride is too slow or too intense, basically every coaster with 1400m will also have an Excitement Rating greater than 7, so you don't have to put too much effort there. But still, add some tunnels, decorations at the station, and cross other tracks just to be sure. Adding another tracked ride like Go Karts to cross the track later also helps with increasing Excitement. Also, leave some room to adjust the lift hill if you got the speed wrong. Consider building two or more stations of maximum length to increase the capacity. Otherwise, rides of 2-3 minutes will lead to long queues. With several stations, even slower (and cheaper) coasters like the Single-Rail Roller Coaster have a decent capacity. This scenario will take you several years in any case, so shaving a year or two off by choosing cheap coasters can't hurt.
An alternative strategy is to close the park and demolish the roller coaster and put in "No Entry" signs on paths that lead away from the park exit. Then, you can remove most of the paths. I only recommend this if you have trouble managing such a large empty park and can't make a decent profit. It takes a while for people to leave with this tactic and it is tedious to get everyone to leave, but you have plenty of time.