Underline particular parts of words in macro

[Ktulu]

Hi guys. VBA newbie here. I use word macros to translate text from Russian to English. I am trying to underline 'TS' of TSIATIM but the macro underlines only the first word.
I don't have the code with me now but I recorded it as below...
Ctrl + home
Find TSIATIM


Press left arrow key one time
Press shift + right arrow key two times
Press ctrl + u
Press ctrl + right arrow key

I put this code in a loop but sometimes underlines from TS are removed... I think the loop should stop at the last occurrence of TSIATIM. But I don't know how to write this code. I don't have any programming background.

I would greatly appreciate any help. Thank you!