Joining new color yarn?

Ready for my second scarf, yeh!
The video on joining new yarn doesnt show from the beginning of a row, so my question is how the first few stitches are supposed to look. Mine show both colors for the first few stitches, is that the norm, or should i be doing some other type of join? Guess i should mention that i am trying to switch between colors every so often
Thanks for any help

If you are working in garter stitch–knitting every row, then your color changes are going to look smooth when you change on a knit side, but will show both colors on the back. It’s the nature of the purl stitch.

If you are changing colors on stockinette and your colors aren’t making a smooth transition, give the tails of your colors a tug to tighten up the stitches at the edges.

Thankyou, now I know i am doing it right then