I am currently doing the samething you are in exactly the same to areas. So this is what I am doing which seems to be helping me.

In C++ :> I am taking code that I wrote in another language and writing it in C++. I am taking Blocks of code that are related that I know work, and I am making them work in C++. Here I am focusing on text only at this point so I can focus on learning the C++ language and how it relates to my game code.

In Allegro > Here I am focusing on learning implementing the Allegro Library and Puting images on the screen. Next I will look at creating my Animations sequences in the 2D format. I am using images from the same game, so that I know they work. This allows me to focus on presenting these images and the animations, without slowing myself down by worrying about the gaming code.

Once I am comfortable with working with both seperately then and only then will I combine the 2 together. That is basically how I handle all my stuff. By focusing on 1 aspect at a time, then copy/paste everything together.