Importing sprites

i want to add my 2-d level design to my Unity project,and i want to import in in layers so that I can separate my background from objects my character actually touches and walks on. However when i import it in umity i have white space around everything and my level looks like different plating cards. how do i fix this problem?

well the seems like the background of your character is white not transparent please check that and let me know

**Note:**some painting programs e.g microsoft paint. cannot do transparent backgrounds
you will need paint.net or photoshop or other programs.