How to create a Map Room / "world map" in Minecraft 1.6+

In old versions of Minecraft I could create a "world map" by making a wall of item frames & adding a map to each frame.

Maps were linked so if I was mapping an area in-game by holding a map it would show up on the linked map of my "world map". Maps would be linked by simply using them in the same area.

I’ve revisited Minecraft in Bedrock 1.6 in a multi-player Realms world & am trying to create a "world map" of our surrounds which shows player positions.

Maps now have different zoom levels & the default 128×128 zoom setting is too detailed. I’d like to use 512×512 (which is the original zoom level?)

But I’ve been flailing around a bit with the cartography table & am getting frustrated wasting resources while trying to work out how the new mapping works.

Could someone please give me step-by-step instructions on how to create a "world map". Or complete the "Map Room" achievement with 512×512 maps.

This is as far as I’ve got:

1. Build 3 x 3* block wall.
2. Cover one side of the block wall with 9 item frames.
3. Build cartography table.
4. Create 9 locator maps(? – do they need to be locator maps to show the player locations on the "world map"?)

…and that’s when I started to get confused.

Any help is appreciated.

*My goal is a 9×9 map of 512×512 maps, but you have start somewhere.