Hi TTerebesi, happy to hear that Sprytile helped get you into Blender! When you import your .blend file into Unity you get a folder called Materials beside your blend file. The materials in this folder is where you would set the texture/tileset.
First thing to do is import your texture into your Unity project and adjust the texture import settings. Select the texture and in the inspector, set it to the following settings.
Next, you'll have to adjust your materials. Go to the materials subfolder and edit each material in there, change the shader to Unlit/Transparent Cutout and set your texture/tileset into the material.
These are basic settings for materials, feel free to play around as you get more familiar with Unity. This material also doesn't do double sided rendering, that's a bit more complex to setup in Unity.
You may see seams inside Unity. The easiest way to fix this is to select the camera and change the Rendering Path setting to Deferred.
Technically, the best way to fix this is to set auto pad offset to 0.20 in Sprytile but unfortunately the defaults aren't set to that.