How to tame an andrewsarchus:

1. Throw honey near it.

2. Once it starts eating the honey, mount it.

3. After mounting, you will need to start steering left or right. There will be an Indicator.

4. Unmount before the red meter fills up.

5. Repeat until the andrewsarchus is tamed.

-Also their saddles protect you from radiation or lava, and gives you infinite oxygen underwater.

Hope this helped!

-Pablo27