How to enable SSH on RT-AC51U (stock f/w)

[BosseSwede]

I would like to SSH into a new ASUS RT-AC51U router running the Asus stock firmware (updated to the lastest release).
But I cannot find where to enable SSH, on the admin page I only find enabling of Telnet, surely it must be better to use ssh?
I am setting it up to use OpenVPN to act as a gateway to Sweden when used in another country.
This part is working fine now, and I just need to activate ssh so I can access the router from the server side in Sweden when it is connected by VPN.
Is this possible on the AC51U?
On my RT-AC86U routers this can be done on the Admin/System page.

When I google I always get onto Merlin discussions and I have not even understood how to get Merlin installed so I run ASUS stock f/w on all of my routers...

 

[L&LD]

You can't install RMerlin firmware on your model.

About | Asuswrt-Merlin

Normally, on a supported router, you simply use the GUI to flash to RMerlin firmware (same as you would do to go back to stock firmware later, if needed).

 

[BosseSwede]

OK, so the RT-AC51 is too limited in its hardware, I guess...
I will just refrain from complicating its use case then.