There is some miscommunication here.
1) I have a category with three products.
2) I made ONE custom field in table PRODUCT with a field type of RADIO BUTTON and gave 3 default values of RED, GREEN and BLUE, AND I added the category I made to this custom field.
3) I then went back to my products, and at the BOTTOM of each one the option to choose from the radio button options I made earlier appeared, and I chose a different color for each of the 3 products, for the first product i chose red, second green and third blue (I also clicked on characteristics but nothing was there, was there supposed to be something there ?????????????? )
4) I then made a filter with a type of Radio Button and and applied it on CHARACTERISTICS (as Mohamed suggested) - also, when I applied it on characteristics, the characteristics dropdown was EMPTY
5) I then made a filter module and added the filter I just made to it, made it appear on the front page and it gave me the error I already said.
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Those are my exact steps, so what do you mean by "custom field or characteristic without any values" ?
I think the problem is with no characteristics in product options, but I don't know how to get them there (as I said when i click on characteristics in product options, it's empty).
Also, I would prefer to filter by searching thru the custom fields, not characteristics (whatever that is)
Please advise
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WHAT I WANT TO DO - in case what i want to do or i am doing something wrong - here it goes:
Like I said I have just 3 products, I want the first of them to be searchable by clicking on red radio box, second by clicking blue, and third by clicking green.