Interconnection between tables

Dear Anthony,

long time since my last post...here I am with a new tricky question:

I have a big database (more than 700 rows x 30 columns) as source of data - let's call it Table1
I have created a new table that pulls out just some specific data from it based on some criteria - let's call it Table2 (much smaller - 50x15)

Now what I would like to achieve is to write some code that allows me every time I change data in Table2 automatically change also in Table 1. Only a numerical value or a string will be entered.
Could you please help, maybe providing me with some simple suggestions?

I hope to have givem you enough information.

Many thanks and regards,
Rita
(attended your course last July)