Starting an Android Activity By Pressing A UMG Button

Hey guys!

**-**I wanted to start an custom android activity by pressing a UMG button How can I implement this ?
**-**And also Do I have to declare the activity in AndroidManifest? How Can I do that?
**-**I have some ideas that custom activities have to be placed in Engine\Build\Android\Java\src\com\epicgames\ue4 ?
I really really need help on this! I’m Almost done with the whole game progress and this is what left of it and its taking too much of my time , I would appreciate any help!:frowning: