Creating a serch feild

We are tryind to create a page that has glossaries in it and client wants to add a search field. Like this it would search blog posts with a tag glossaries or something like that.

We are not sure that this is possible with this platform. The alphabet row is not hard just the search field is a bit of a problem. Now we are using a template edition. And if this is possible could someone point me in the correct dirrection.