Inside the Frontier repo, I found this template folder: https://github.com/paritytech/frontier/tree/master/template
and its Readme says:
This template is maintained in the Frontier project repository, and can be used to generate a stand-alone template for use in an independent project via the included template generation script.... This is Option 1. That is to manually run that script.
But then further down that Readme, it says
To build the chain, execute the following commands from the project root:... this is Option 2. That is to build it via
cargo build --release
Also I am aware of @JoshOrndorff's tutorial about how to add Frontier into a Substrate Node Template: https://github.com/PureStake/substrate-node-template/commits/frontier-workshop-2021, but that is a few months old. This is Option 3: that is to add Frontier code to the latest Substrate Node Template...
I am very confused by those options.
After fixing the Frontier with the correct Substrate version I need, how can I build a demo for running Ethereum smart contracts?