The marker (rings) are a visual cue in your project, whether it is worked flat or in the round.

Think of your work as a graphic; there is an X axis (horizontal) and a Y axis (vertical).

The stitches are on the X axis (horizontal) and the rows on the Y axis (vertical).

The stitch markers (rings) are on the needles and can be used to mark the beginning of the row (work in the round), to delimit a section of a pattern (lace, cable, ...) or to indicate a subtlety (e.g. an increase/decrease).

For crochet project, I advise you to use Frédérique markers.

The progress keeper and row marker are used for visual cue and allow you to see easily where you were.

It is commonly used to count your rows (e.g. from last inc./dec.) or see how far you've knit in one session.

The Cido marker is not design to stay in place for a long period of time as I designed it to be easy and quick to remove and put back on your project.

It does a great job as a progress keeper or for marking short repeats (like a decrease every 3rd rows).

The row marker Frederique is the one I specifically designed to stay in place for a long period of time.

This marker will not slip out on its own.

To place it, insert it in a stitch then turn it on itself to fix it.

It can be used for the same purpose as the progress keeper.

You can see in the video how to do that (the comments are in Frenh).