Hope that schedule works well for you, Halidon (and anyone else).
I keep meaning to write up these sorts of things in detail, but here's a couple of pointers. Maybe I can put this toward that goal.
You can import one of those schedules for the first season. Then you could import the other at the start of the second season. Some people might advise not doing the import until some certain point like at the end of the preseason and spring training and right before games are to begin, but I've never had any problems importing any time during preseason and generally do it first thing after proceeding to a new season.
What I would advise before importing that other schedule for the second season is going into the .lg folder for your league and making a backup copy of the "schedule.dat" file and storing it somewhere. In fact I would do that potentially each season before bringing in a new schedule.
What OOTP will do when going from one season to the next is mix up the teams in the schedule - games are not moved, but different teams within a division get slotted into those games. For instance, every game slot that had held the 2nd team of a division might then hold the 3rd team of that division. If you save that schedule.dat file, you will have the schedule you imported for the previous season with the same numbers of intradivision, interdivision, and interleague games but with many possible such rearrangements of teams.
If you simply re-imported these two schedules in alternating years, teams would always be playing the exact same teams at the exact same times. You probably would get tired of your team playing the same team in the last series of the season every year. So you can simply copy a schedule.dat file into the .lg folder for the league and replacing the one there. Like for the third year, rather than importing the first schedule again, outside the game overwrite the schedule.dat file in the .lg folder with the file you stored at the beginning of the second year. But before doing that, save a copy of the schedule.dat file to copy in the same way at the beginning of the next season. And so on and so forth. You would only use the import function in the game once for each schedule version, then afterwards just be moving files in the file manager outside the game.
Kudos to Go Tribe for thinking of doing this. Hopefully I explained it clearly enough. Just remember to be careful when moved, copying, replacing files. Backups are your friend. Though I would not expect any problems at all since this is basically the same method of copying .dat files is the same as using Stickware, if anyone notes a problem with this method, please mention it.
One issue with that above method is that your calendar losing a little touch with reality. Games will always be on the correct days of the week, but the days of the week will be on the wrong calendar days. For instance the season in that above 144-game schedule will always start on Monday April 19. The only problem is April 19 is not really a Monday every year. But it does not affect the game in any way, and I think most people besides LGO and myself would either never notice or never care. But if you were curious, you could check out
this thread. That though is definitely Advanced Scheduling, or at very least not basic Scheduling 101 and not really need-to-know stuff.
Another little issue is that teams might get more really long or really short homestands and roadtrips when the game switches up matchups. But travel does not affect performance (yet, but I think LGO is looking forward to the day...) so it is another cosmetic thing. When I make up a schedule I try to make realistic length homestands & roadtrips, but I know I make too many that are just one series in order to get it done. Plus I have no idea if a one-series road trip is for a New York team going to Boston (seems plenty realistic) or for a Florida team going to Tokyo (not so realistic).