Maybe you could start off by adding the lines over a photograph, could be at the computer or in a newspaper/magazine idk whatever fits you best and then try to recreate the lines on paper, to check if you understood where the lines should go. Sometimes i do this when i'm having a hard time finding the angles.

I did those on paint https://imgur.com/a/P03KXqE

The Loomis method can be kind of confusing at first, it's kinda tricky on extreme angles, it took me some while to get used to it, but once you do becomes very intuitive. The most important thing is to understand where you should be looking for the angles, Proko explains this in his videos.

There's a Steve Houston video in which he explains how to construct the head, i don't think he mentions the Loomis method, but it's basically what he's talking about, and he also explains how this was applied in some artworks. His approach is very constructive and didactic.

https://www.youtube.com/watch?v=2T7cDY7YDsg&pp=ugMICgJwdBABGAE%3D

If you already saw this then nevermind lmao.

Anyways, hope this helps!