Adding a search box or keyword search

Need some help coming up with the HTML code to create a search box and button for inputting a bib number
When a bib number is submitted (for example 2806) it
takes you to this address: https://www.werunracephotos.com/keyword/OBH2021;2806/
Search box should have Input bib # inside of it and only accept numbers

This is basically to add a keyword search box to a page. I know you can add a search box, but the page it directs you to does not allow you to download directly from the page.

The search box takes you to this page: which does not have the free download button below it.
Need it to look like this instead Notice the free download button below each photo.

Need a keyword search that gives you a url with keyword in it. There is a difference in the layout of the page rendered after a search and the page you get with keyword.