Add redeem instructions

[zognin]

Closes #268

Can someone help test whether the ? button works in mobile because sometimes it works and sometimes it doesn't for me
Can someone help check the aspect ratio on big screens too? Cos I don't have a big screen.

Notes

• Haven't added animations of instructions opening and closing
• Slide content can prob change later, for now it's just the bare min
• The ? button for mobile should be in the nav bar but for now it's like that because it's going to take a bit of work to do that so it's prob better to do that in another PR

[sivayogasubramanian]

LGTM!

This is what it looks like on a big screen

2022-10-23.20-40-12.mp4

I think the instructions can just be a normal modal in desktop?