$1911

Hello everyone! I'm new to this forum, so apologies in advance if I'm doing something wrong.
I love pattern #A30354, but I'm confused how to switch the background colour in the middle. I have found this tutorial: friendship-bracelets.net/tutorials/152 but I'm not sure if it fits, since it uses three colours in the "Background color substitution" section, not two... And because of this I don't understand how many of the 17 strings should be red and how many black.
Any advice? I may be missing something obvious, I'm very new to this hobby.

In alpha patterns you usually have base-strings that are not used for making the knots, and a string that knots around the base-strings. That’s called the substitution method. You swap colors whenever you need to make a knot in a new color.
If you don’t want that and the pattern has only two colors you can use the two-colored alpha method. That means you have base-strings in one color and another very long string in the second color.

Thank you very much!