I use Blender and Substance painter for all of my model and asset work. I use Clip Studio Paint for my substance alphas and free textures.

The alpha packs are made for substance painter! Just unzip the provided .Zip file and drag all your alphas into the substance window! - Secret tip, Shift clicking like you would do in file explorer will select all alphas if there's a lot, and you can assign them at the same time via the dropdown as 'alpha'. The alphas main objective is to be a stamp for higher detail graphics you otherwise won't be able to get with painting alone! I tend to release many free ones and update pre-existing packs to account for seeing models with nice pretty details!~ <3

Inside of the provided Unity package! Simply navigate to the 'FBX' folder, click into it, find the model inside and right-click, and 'Show in Explorer' (Second from the top). From there you can import the model into Blender by importing via. FBX and drag the file from the file explorer into the Blender window. All assets and models come with an FBX file and it's easier to store it in the unity package as opposed to having a duplicate FBX hanging around with an already overinflated file size to account for substance painter files provided.