Open Poor Maps
Open Poor Maps and access its tools by pressing the button in the bottom of the screen (highlighted by red box in the screenshot).
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Basemap
To configure drawing of the maps, click on "Basemaps", as shown.
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Select OSM Scout Server among the list of basemaps. Its recommended to use @2x for faster rendering.
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Search
In Poor Maps tools selection, select "Search", as shown.
In Search, choose OSM Scout Server as a search engine provider, as shown.
Navigation
In Poor Maps tools selection, select "Navigation", as shown.
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In Navigation, choose OSM Scout Server as a search engine provider, as shown.
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Mode of operation
You are all set! Don't forget that you need to have OSM Scout Server and Poor Maps running simultaneously for offline operation.