"Maps" are typically whole World saves. You should just be able to download the file, extract it, and put it into the "saves" folder in your Minecraft.
For example, a 3/4 magnification map has a pixel size of 8x8 blocks; this means the map will read only the top-most opaque blocks at the 0,0 coordinate, the.
We are running the latest 1.19.73 on Android and downloaded some 1.19 maps. We unzip them in the minecraft worlds folder, and see them in the list worlds.
This guide will cover everything you need to know about Maps, including how to make a Map in Minecraft, what to do with Empty Maps, step by step instructions.