More detailed reply:
tilemaps are a grid of small images as you have obtained above.
To make a png file to use as the image for your tilemap, first you must decide what grid to use. I recommend since you have 11 tiles, doing a 3 along and 4 down tilemap, with each tiles resolution taken into account.
example, if your tiles are each 128*128 square pixels, your tilemap will be 128 * 3 across and 128 * 4 down.
The tile map selects tiles from left to right, then down 1, then left to right again and so on. So you want to place your tiles in the png file as such:
1 2 3
4 5 6
7 8 9
once you made your 3 * 4 tilemap saved as a png, just create your tilemap object and load that png file into it. remember to specify the dimensions of your tilemap grid (3,4) and the resolution of your tiles.