This app is Toolbox: https://play.google.com/store/apps/de... Although, I won't recommend you to use as it has removed the support for JS(ModPE) and support for lua is being worked on so instead use another app called BlockLauncher: https://play.google.com/store/apps/de... It has support for ModPE and works pretty well.
All the steps given in video are for toolbox which is now outdated so follow the steps for BlockLauncher:
1)On top-middle there a small wrench-like button which indicates settings.
2)You click it and then you select ModPE and import the thing you want to use.
GOOD LUCK! (Consider subscribing too! :D)