Answer 1

you want the ⚡ tab for challanges after you press on this look for the green ➕ tab at the botton of the screen, select your weapon then select somone to challange

For quiz factory its inside the 3 dots tab at the top right corner of the window

best of luck.

Answer 2

Challenges can be found by selecting the "challenges" tag in the Q&A Discussions.