Very very new to all this fun!!!!!!!!!

Hi I am able to use dvd shrink ok and create a selection of clips from one dvd, that burns and plays fine.
I want to ad some other clips from another DVD in the same box set
when adding the additional track I have given the additional vts bup and vts vob and vts ifo the next available number in the compilation i.e. if the last No on the playable collection is 8 the new track becomes 9 etc.

what do I do regarding the VIDEO_TS.IFO & VIDEO_TS.BUP of the new track as I assume I don't use these, but I think I need to alter the originals?

Hope this makes sense

Paul