How can I play animations one by one in sequence with animator controller ?

Should I use Timeline and create there one long animation clip with the all the animations ?
I have 12 fbx files. Should I add each one of them to the animator controller and connect them all by transitions? Or there is a easiest way to do it ? The animations files I downloaded as pro pack from Mixamo.com site.

So I wonder how should I play them all one by one ?

 

Thats a good approach, I consider that to be the easiest. You can set them to transition from each other using triggers - example: if you only want your character to jump while its running, only connect your "jump" state to the "run" state.

Also, if you don't need that kind of restriction, you can connect "Any State" to all of your states and use triggers too.