How to clone dotCMS demo website

[N S]

Hi there,

I'm pretty new to dotCMS and Docker.
What I'm trying to do is to clone the dotCMS demo website.

I have 2 issues regarding it.

1. Cannot set up .env file.

I cloned the repo from https://github.com/dotCMS/dotcms-nextjs-starter

Watched two videos from dotCMS:
Making your #Jamstack application editable in real-time with dotCMS
(https://www.youtube.com/watch?v=3vjdxjfkZRQ)

Build and deploy your #Jamstack with #dotCMS, #NextJS and #GraphQL

(https://www.youtube.com/watch?v=iYH3d0UAew0)

Ant I did exact the same as the speaker did.

But when I try to set up .env file, it gives me an error:

"Problem with your DotCMS instance

ERROR: request to https://starter.dotcms.com:8443/api/v1/authentication/api-token failed, reason: self signed certificate"

2. Running dotCMS on Docker

Also, when I run doctCMS on Docker according to this guide:
https://starter.dotcms.com/download/

I can log into http://localhost:8080/dotAdmin 
But http://localhost:8080 gives me 404 error

I'd really appreciate if anyone could help me figuring this out ;(

Thanks!