The path from the exit of the coaster in cell 1 will lead into cell 2. From there, you basically build a mini park. Put rides and stuff in it, whatever you want, as long as you only have 1 coaster. The exit of that coaster will then lead to cell 3.
Todd is right, basically each cell is a mini-park.
To distinguish (or separate) each cell, you can use either or all of the following methods:
1) Different colored landscape.
2) Walls.
3) Fences.
4) Any other scenery.
5) Change in land contour.
6) Lake or river.
7) Whatever, as long as it looks separate from another cell.
In each cell, you can have:
1) Zero or more 'regular' flat rides.
2) Zero or more food booths.
3) Zero or more park staff.
4) Zero or more scenery.
5) ONE AND ONLY ONE COASTER whose excitement rating is greater than the previous cell AND whose exit leads directly (i.e. no intersecting paths*) to the next cell. Once in that next cell, you're basically in a 'new' park so to speak.
6) One or more 'special' flat rides whose exit has two choices for the peep to make: one path that leads him/her back to the previous cell and one path that leads him/her back to other paths in the current cell (see Todd's and my previous posts for more details to this rule). Also see that marvelous screenshot that Becky made.
7) Zero or one "I want to go home, mommy' paths that lead from the current cell directly back to the first cell with a 'no entry' sign where this special path enters the first cell to prevent peeps in the first cell from cheating the system.
8) Rides (coasters and transports) can extend into another cell from their 'home' cell as long as all of their entrances and exits exist only in the 'home' cell. Meaning I can build a coaster that starts in cell 4 and goes into cell 5, but ends back in cell 4.
9) The layout of all rides within your cell is your choice as long as it follows these rules. The coaster could be the first ride that a peep encounters or the last.
Todd, Becky did I miss anything?
* - No intersecting paths for peeps to cross; staff members is a different story... I hope!