Access two tables synchronization, How!

Ok… first I’m not an DB expert like all of you, just a common break fix guy!

Facts:
a) inventory db has over 10500 records
b) inventory from various manufactures are changing nightly.
c) flat delimited text files that I have to download nighltly.

Problem:
1) how can I synchronization my inventory db on my main inventory db on a nightly schedule, to reflect only the new changes from the other manufactures flat files that I have local?

Any succestions would be greatfull…

thks… Gary