Nexus 7 2013 LTE upgrade path

[AC Question]

I have a Nexus 7 2013 LTE.
It is running Android 4.3 (Jelly Bean)
It is not rooted.
When I check for updates, it shows "Your system is up to date".

1) I would like to upgrade the tablet to the latest version available on it, which I believe is 6.0 (Marshmallow). Will I have to go via every intervening version?

2) What is the recommended method of upgrading?

Any help would be appreciated.

Regards,

Mycroft