How to add an ITM to a Kit upon level up and upgrade it at certain levels?

OK I am new to Modding, and I am not a programmer, but I have a kit I am working on and I want to add a feature. Upon leveling up to 3 I want to add an ITM file to the Kit. Then again at 6, 9, and 15. I have the ITM files written and ready to go, the information for the ITM's is in the TP2 file. I can CLUA them in, but I want it to be automatic, with maybe a "Your weapon has improved" statement.

Any help would be very appreciated.

TIA.