Just a quick note to anyone installing Vaultwarden from the github repository in order to get the admin page to work I edited line 36 to look like this:
[“-e”, “ROCKET_TLS={certs="/ssl/certs.pem",key="/ssl/key.pem"}”],[“-e”, “ADMIN_TOKEN=PutYourAdminTokenHere”]
Not sure if this is the best way but it worked for me!