Realistically, unless you're willing to totally wipe your computer, the only answer is to get a month of an InDesign subscription.
Trial periods can't be extended. After a trial expires, you need a serial number to install the software as a licensed version to activate the software to continue using it.
Adobe trial software is time-limited, and otherwise has the same feature set as the licensed version. Some scenarios can cause trial software to expire early:
- Changing the system clock
- Modifying the executable file
- Attaching a debugger
- Automated virus scans
The trial period starts when the app is installed for the first time. For Creative Cloud apps, the trial period is seven days. When you download an app for trial, the app is installed and launched automatically. Your trial also starts at the same time. For example, if you download and install a Creative Cloud app on the first day of the month, but start using the app only on the fourth day, your trial still ends seven days from the first day.