Some Troubleshooting Steps to try if you can't tell if the mod is loaded or not
Read the troubleshooting document that comes included with the mod now! This pretty much has everything I have below and much more!!
You can look in Game Options/Other/Custom Content and the mods should show-up as loaded in the Script Mods section. Make sure you have the checkbox on Game Options/Other checked for allowing script mods.
As of version 1.13 of Sims 4 (Get Together Expansion), any time EA releases an update, they are forcing the settings of the game to have mods disabled. Ensure that if an update from EA has just been applied that both checkboxes for Mods are enabled: the checkbox for enabling mods and the checkbox for enabling script mods.
From your home lot, you can open the cheat console with CTL-SHIFT-C and type "mc_help". If the mod is loaded correctly, this will give basic command-line function help. Additionally, you should be able to click on a computer in a game lot or on a Sim and see a "MC Command Center" menu.
If the mod is loaded but you can't tell if it's working (you haven't seen pregnancies or move-in notifications), turn on logging in mc_settings.cfg by setting Logging_Enabled to "true" instead of "false". When you run the game and your home lot loads, if you go to your mod folder and open the mc_cmd_center.log file, it should have "Initializing Alarms" at the top of the file. Every night at midnight, alarms will run and this log file will have updates in it telling what happened for that day when the alarm ran.
If the mc_cmd_center.log file doesn't exist but according to the Game Options/Other/Custom Content window, the script mods are all loaded, then you may have a version problem. You can look at the LastExceptions.txt file in the Sims 4 folder to determine if that's the case.
You should verify that your mods folder looks similar to the screenshot attached to this page. The versions on the mod names may be different as the screenshot is older, but the location and names should be similar.
You should ensure that you have at least version 1.9.80 of the Sims 4, or your game will not detect the ts4script extension. That was added in that update from EA. It is recommended that you have the version displayed in the compatibility section above as that is the version I have tested with and know for sure everything works correctly with.
There are some mods that are known to conflict with MC Command Center. This is usually caused by functionality in those mods that is already in MC Command Center so a separate mod is not needed and causes problems. Known examples of mods that would cause problems are:
Autsave for Sims 4 by sachamagne
"Neia's No More Same Sims Everywhere" and "Autosave" mods.
TwistedMexi's Always Testingcheats mod, but I'm not sure if it works even on its own or not.
As of version 1.13 of Sims 4 (Get Together Expansion), I believe Pregnancy Mega Mod also causes some problems but I don't think these are conflicts, I just think it doesn't work as-of that update. PMM options should all be available from the MC Pregnancy module.
The "Sticky Clothes" Mod conflicts with my mod as I also have that functionality built-in to MC Command Center automatically.