When you’re ready to change colors (to color B), you’ll almost finish the line you’re working on with color A. However, when crocheting in a row, you need to make sure you’re thinking about the right side and the wrong side, as both are likely to be seen and shown. If you want to use color A again in the next few rows, don’t cut the yarn. Leave it tight so you can wear it up the sides and avoid having to weave in the ends. Learn the best way to change colors when crocheting patterns.
However, there’s one more thing you might want to learn, which is how to change the colors in the middle of the row.