rulers

Hi Reine,

in the current Inkscape version, there is no panel that allows you to see a list of all guides or such, if you mean that.

To create a guide, drag it out of one of the rulers.
To rotate it, hold Shift and move it or double-click on it.
To label it, double-click on it.
To move it, drag it or double-click on it.
To change its color, double-click on it.

To add several guides at once, use an extension (e.g. this one: https://github.com/sambody/inkscape-guide-tools)

To lock it, wait for Inkscape 0.92.
To keep selected color when reopening document, wait for Inkscape 0.92.

Hope any of this answers your question, if not, please be more specific with your question.

Kind Regards,
 Maren