You should be able to hit enter in the search field on your phone's soft keyboard (or the button might just say search). Which phone/operating system is this?
Chrome on android.
In Firefox on android I can see the label "youtube video url" (in Chrome I thought it's a query field for words to be searched). But in Firefox the on the page images are not rendered - the page look strange.
I think it's easier for you to try yourself on android phone. Maybe it's only me. But I browse a lot on that phone, only lexica.io works strage.