New to this Calendar help!!

Hi Guys, I'm after some help. The problem i have is I've created a web app using a app builder platform for my sons football team. for their fixtures i wanted to use a calendar with agenda and possibly link it to google maps for away fixtures. however google calendar does all this which is great but when I link it to the web app it wants to open in full screen outside the web app. so -

I thought i'd try this calendar which seem very similar..... Good news is it opens within the app like i want it too but it opens it like it's not logged in to any account, I have shared it and copied the correct I would love it to open and just show the agenda's (In my case just fixtures) then my users can click on a fixture and it then brings up details with a link to the map.

Any suggestions/help would be gratefully received - I'm no code expert so easy answers would be even better.. :)

Thanks Paul