The feature to live stream to LinkedIn is only available to approved LinkedIn live broadcasters. You will have to apply with LinkedIn to be able to Stream Live using Wowza Stream Engine.
For your reference: https://www.linkedin.com/help/linkedin/answer/128901
LinkedIn Live Broadcast Page
Note: Pick a region closest to the Wowza Streaming Engine server instance location to get the endpoint details.
Example endpoint details provided by LinkedIn:
Endpoint String: rtmps://1_abc123de.channel.media.azure.net:2935/live/1_wxy234z_5
Stream Key: 1_wxy234z_5
Configuration within Wowza Streaming Engine Manager
Manual Configuration within the pushpublishmap.txt file
[your source stream name here]={"entryName":"LinkedIn Example Stream Target", "profile":"rtmp", "application":"live/1_wxy234z_5", "port":"2935", "sendSSL":"true", "destinationName":"rtmp", "host":"1_abc123de.channel.media.azure.net", "streamName":"1_wxy234z_5", "enabled":"true"}
Note: You will need to manually add "sendSSL":"true" property in the pushpublishmap.txt for RTMPS streaming.
Please refer to this article for more details on how to do this.