How do I reinstall widgets on Samsung a5(6)

[Android Central Question]

I erased a few of my widgets on my Samsung A5(6) just before Christmas but today I bought mirascreen dongle but can't seem to get it to connect to it through my phone but I can connect it up through my tablet as my tablet has the cast widget. Does anybody now how to get the old widgets back on my phone or to reinstall the cast widget or the mirror cast?