Problem with virtual hosts, ssl, strict transport security

Nextcloud version: 11.0.3
Apache version: 2.4.10
PHP version: 5.6.30

Hey people,
I was able to get my nextcloud installation up and running but now I am facing problems when trying to redirect traffic to https and setting strict transport security.
I am trying to follow the Documentation and edit my virtual hosts file.

I am running some website at mydomain.com and running my nextcloud at mydomain.com/nextcloud
At the moment both pages are reachable.

The VirtualHosts File for my website contains some VirtualHost:
<VirtualHost *:80>
´ …

The VirtualHosts File for the nextcloud instance contains:
Alias /nextcloud “/var/www/nextcloud/”
<Directory /var/www/nextcloud/>

I tried to follow the documentation and add VirtualHost directives to the virtualhost file of my nextcloud installation. But I do not know what I am doing and everything I tried to change just caused apache to dont start anymore.

Could you please help me and tell me how the virtualhosts file for nextcloud would have to look like so that both all unencrypted traffic is redirected to https and HTTP Strict Transport Security is enabled?
Thanks in advance!
Cheers Leon