Malai,
perfect for what? You wanted to know how to get the router acting like a firewall. Putting the access-lists on is the first place I'd start. After you reapply the access list you'll have to figure out what if anything you broke, and then if this is line with whatever policy you happen to be setting this up for.
the earlier advice you received to remove the access-lists was in aid of getting it up and working. Once everything seems to be good, you can reinstall the access-lists knowing that it used to work and that the last change broke it the way you expected or did something you weren't expecting.
It's a good idea to figure out what your policies are, and then figure out what systems you need to enforce this.
Tony
