One of the aims of this paper is to provide a simple and replicable approach to estimating
a conditional asset pricing model. Similar to the two-pass approach used in the standard
CAPM, we adopt a three-pass methodology.

文章中主要用了three-pass methodology(也就是三个步骤),并且提到了Similar to the two-pass approach used in the standard
CAPM，即传统的CAPM模型中采用了两步，想请教一下，采用了哪两个步骤？因为这样有助于理解下面的three-pass method