The new Homematic integration currently is available as a custom integration. It can either be installed manually, or using the HACS integration. The latter method is preferred and what these instructions are based upon. Using HACS will also allow you to upgrade the integration later on. More detailed instructions can be found here: https://github.com/jens-maus/RaspberryMatic/wiki/HomeAssistant-Integration

In case you don't have HACS installed already, follow their instructions. Please be aware, that because of the way HACS works, it might take a while for the installation to complete / be useful due to the API-rate-limit of GitHub. It might take up to one hour for all the default repositories to be loaded.

Once HACS is operational, you can follow these instructions to add the repository for this custom integration. The Repository URL to add is: https://github.com/danielperna84/custom_homematic
With the repositoy added, you can then download a specific version of the custom integration. Choose the latest version available. You'll be notified, that a restart is necessary to complete the process. Perform the restart (of Home Assistant) to finish the installation.

After you have added the repository and installed the custom integration, you should be able to activate the integration just like any other integration via the Integrations-UI of Home Assistant. The name of the integration is Homematic(IP) Local.

During the configuration flow you will be asked to enter serveral values to establish the connection to your Homematic hub (CCU, RaspberryMatic, Homegear etc.). These are very similar to the values you have already configured for the old integration via the configuration.yaml file.
IMPORTANT: When the version of the integration is < 0.26.1, initially the integration will only expose 1 service + entities for the available variables on your CCU. You then have to reload the Integration manually once more after configuration. After that the devices and entities should be available.