How to wear Runes??

I am a level 11 R/E wearing Fir-Lined armor and can't install any Ranger runes. They just give the circle slash when I try to put them on. I have the following Runes. and none will go on. Any help??
Thanks
Ranger Runes
+1 Beastmastery
+1 Expertise
+1 Marksmanship
+1 Wilderness Survival
General Runes
Superior Vigor +50 Health

Double click the rune and click on the armor piece you wish to apply it to.

For weapon upgrades it is the same, double-click and click on the weapon.

Note that only the best rune applies and only 1, so using 2 Expertise +1 still provides only +1.

Great --- Thanks

As a suggestion, I wouldn't use that Superior Vigor rune unless you don't plan to upgrade your armor for a long long time. Superior Vigor costs 75k at the rune trader, so placing it on weaker armor would potentially be a waste if you botch a later salvage attempt to get that rune back out again for a better set of armor down the road.

I only use Superior Vigor runes on armor that I plan to keep for the lifetime of my character. Everything else, Minor or Major Vigor is fine (and much cheaper).