More questions on crystal report(編號:2895)

I want to ask the followings:
1. How can I place a textbox data from VB to crystal report in a certain position?
2. How can I setup one column in the report and compare with 2 item, just say a and b. If a > b then that column has a tick, else remains blank. How can I do?
Thx for the answering first.