Ok, I recently got a new computer for work (not by my choice). What I want to do is deactivate Acrobat X Pro from my old computer and activate it on my new computer.
Someone from Adobe Support gave me the link to download X to my new computer. I did not have the serial number when I did this. Now I have the serial number to enter.
Where do I go in the program to enter the serial number if I am currently in the 30 day "trial" mode?
As per the description given above, it sounds like you are willing to install the Acrobat X for which you have the serial number to activate.
I assume, that the current version of the Acrobat that you have is the latest Acrobat DC not the Acrobat X. Because there isn't any 30 days trial version exist for Acrobat X.
Check the current version of Acrobat that you have installed, upper left corner you can see the name. If its Acrobat DC then you need to uninstall first.
Use the cleaner tool to uninstall the existing version- Download Adobe Reader and Acrobat Cleaner Tool - Adobe Labs
And then download the Acrobat X through the link that you were given. Or you can install through- Download Pro or Standard versions of Acrobat DC, 2017, XI, or X
Enter the serial number to activate the license when you get the prompt.