how to combine maps

Dear peers.

I just joined the community.
I have little Knowledge of the system.
I have downloaded a map from another country were I leave and there are cities of that country not shown when I type part of his name.
It opens a menu “search all cities”, then the street name is asked, it type it, them I see " no matches".
Is this normal since I am far away from that country?

Also, how can I combine, por example three european countries in only one SD card?
I have a 2009 Nuvi 360 Garmin.

Thanks for the possible help.

Kind regards.

For Garmin maps please use the Garmin maps forum: https://forum.openstreetmap.org/viewforum.php?id=26

Thanks and kind regards