Learn more about Lokalise Messages for Front in the corresponding article.
Index
Enable Lokalise integration
Once you've logged in to your Front account, proceed to Settings by clicking a gear icon:

Then go to Integrations and search for "Lokalise". Click Enable the integration.
Authenticate Lokalise Messages through the sidebar
A new L icon should appear in the right-side menu. Click it:

Then click Authorize in the sidebar widget:

Confirm the authorization on the pop-up window for the Lokalise Messages:

After the authorization is succeed, check the Lokalise widget and enable the webhooks:

Enable and set up webhooks
Go to Integrations in the left side menu and find Webhooks in the integrations list:

Select it and click Enable:

Once enabled, set Enabled and Send Full Event Data switches to On. Then click Save:

Set rules to trigger a webhook
Proceed to Rules > Company Rules > Add a rule:

Set the conditions as marked on the screenshot below. Specifically, make sure to provide a proper Webhook URL: https://messages.lokalise.com/v1/frontapp/event.

Further steps
Read Tutorial for agents to learn how to receive and send translated messages to your customers
Learn how to configure languages: globally, and on per-agent basis