Shin Yokohama transfer

Hi
Will be heading west from Tokyo but the easiest Shinkansen leaves from Shin Yokohama att 6:00. The first train to arrive Shin Yokohama comes at 5:44.

Will carry a backpack and a medium suitcase. Seats reserved at the back so I can put away the baggage.

I am curious if 15 minutes is enough to clear the transfer from the local train station to Shinkansen platform. I guess there is no rush hour by then.

The map seems to involve some stairs and elevators.

I don't really know about Shin-Yokohama station, but it's always safe to have some spare/back up time, when going from one platform to another. And around 6am could get busy around, if you are in urban city. There are many stairs in Japan anyway

Shin-Yokohama station is not big. 15 minutes would be fine.

That should be plenty of time. Particularly as you say you have seen the map so you know where you are going. Stairs, escalators & elevators are available.

Which date and dep station(which line) name?

This is station map without Yokohama city subway called "Blue line" as line nick.
http://www.jreast.co.jp/e/stations/e888.html

This is not written in EN, but including city subway.
http://www.ecomo-rakuraku.jp/stationmap/23212.html
This is opposite way fr Shinkansen platform to subway ticket gate, about 4 min.
https://youtu.be/BGZNl1EsU1c

Whether you're coming by Subway or JR Yokohama Line, 15 min. should do.

Be sure to look above for signs showing you the direction to the Shinkansen, and ask a person in a station uniform whenever you're uncertain about something. It's not a straight walking line, but the signs should appropriately take you there.

But keep in mind that delays and accidents can happen. If possible, show up early and rest at the tiny lounge on the platform. The Shinkansen platforms at Shin-Yokohama offer nice views too.

Make sure you follow the signs closely. It should be possible but I used to get mixed up at Shin-Yokohama station on my first couple of tries there. They may have improved signage since 2014 though....