Confused beginner trying to understand "lo"

[k-dawg]

I have been listening to audio CD's of Michel Thomas and am on the 5th CD of 8. I am comprehending almost all of it, but I seem to be confused with the application of what appears to be almost the most simplistic thing.

I think I am just confused and trying to figure where I have lost the application. I have tried going back and listening to previous CD's to find where I have gone awry to no avail.

I contribute along with the CD's and I come across a phrase and the two people in the studio say it one way and I say it another. Then I swear it switches and I do it again, except the opposite.

Just for a quick example, the context is "...hacerlo" but from listening, the correct way to say it (in the context) was "...lo hace"

I think that I am getting confused with all the "he, she, them, they, it"