how do I add sub category product links in wordpress sidebar

Does your theme show child categories at all?

Not sure what you mean but it doesn’t show any subcatagories ar all.
see https://howtobuildplans.com/

THANKS!

Try checking “Show hierarchy” in your Category widgets.

Thanks and I do have that checked

Well, it works fine for me in Twenty Ten.

Got it to work buy adding the url in the text widget I have for the products categories as before.It wouldn’t work earlier. Will that be ok for SEO? Thanks.