APT VS CAPM

I never was good in economics.

APT allows you to form a more detailed model for a particular asset, so you might create a model that takes into account how an asset performs against similar assets (for example changes in market demand for that class of investments) and also how the entire asset class performs against macro economic effects (say interest rate hikes). The challenge with APT is that you can devise many different models with different variables. APT doesn't tell you which variables to use, it just tells you have to compute expected return using the model you choose. CAPM is far less detailed, but it is also a lot easier to use. You can easily get all the information you need online for publicly traded assets.