Make a standard drupal 8 installation and enable all addons/modules/themes on the new site you require.

Make sure you have the following modules enabled:

• migrate_plus
• migrate_tools
• migrate_upgrade

I use drush in a multisite configuration:

drush -l https://uri migrate-upgrade --legacy-db-url=mysql://password@localhost/dbname --legacy-root=https://drupal7uri  --configure-only
drush -l https://uri migrate-import --all