This may seem obvious (and the list of steps might be a bit patronizing, skip them if you're comfortable with them. Think of them being for the next guy that shows up).
I'm assuming that you have three bug reports rather than bugs.
First step is Duplicate
Second step is Document (report defect)
Third step is Demonstrate (write test, manual or automated)
Fourth step is Delegate (get someone else to fix it! or fix it yourself)
Fifth step is Discriminate (Does the fix really fix the problem)
Sixth step is Document (again)
Seventh step is Disseminate (deliver)
There's no "magic" way to approach testing. Sometimes you just have to dive in up to the elbows and start throwing stuff around. Having a wide range of tools available to you is a good thing but only when you've figured out how to do something by hand can you automate or approach something differently. More comprehensive methods only work when you have an entire release to test and manage. For three bugs, you're just caught slogging through it the first couple of times until you find other ways to eliminate the "labor" of testing. Without knowing the product and how it works (and no, I don't think we really want the details) we can't make specific recommendations. But even if we did, we'd all have different answers about what tools to use and how to use them.