Then you have to get the BR and watch it, before going to see TS2. TS2 only makes sense if you have seen TS1.
You have to remember that TS was made on a shoe-string budget of just £1.5m on Super-16 footage and they had to dub the entire movie, as they did not have the budget for location sound and the hire of proper sound-stages, but built the sets in a disused factory in Glasgow.
The incredible use of music in was only made possible on TS1 by David Bowie, who had seen Boyle's movie 'Shallow Grave' and was a fan and therefore jumped in at the last minute to make the clearance of all those hit songs possible.
As an homage to Bowie, the relentless soundtrack on TS2 goes silent as our main protagonist, Renton, goes through his old record collection and stops on a David Bowie album.