Start at developer.marketo.com.
This is far too expansive a question for a simple Community thread, though.
If you don't have a lot of tech resources to build/maintain custom ELT, then you may want to look at services like Stitch or Fivetran. Both have Marketo and Snowflake connectors out of the box and a non-developer can be up and running in an hour or two.
It would also be a good idea to reach out to your Customer Success Manager at Marketo so that they can pull in the relevant teams to help assist with your questions regarding integrations.
Thanks! We have already integrated with REST API method, no worries.