Silly mixup when knitting stitches

Can someone help me figure out how to repair this mistake? I’d imagine it would be simple to un-do… Please & Thank you

Because I don’t have the vocabulary quite right yet, my question comes in the form of a Youtube video (once again) :

One of the things you can do to fix this is to undo the stitches that are wrong. An easy way to do this without losing stitches it to "tink"or knit backwards.
It helps, especially when you start out, to finish a row before you put your knitting down. It’s so easy to pick up a partially finished row and start knitting stitches in the wrong direction.
(Perfect title for your thread, btw.)

It worked! What a relief! Thanks : )