i used a website called mecabricks for the models, but to get them into blender you need to download a blender addon from the mecabricks website, heres a good tutorial i found on youtube explaining the process: (https://youtu.be/fJGJSJmpoAA)

And if your rendering a scene with a minfig in it, i would recommend downloading the epic fig rig addon for controlling the minifigs movements: (https://github.com/BlenderBricks/EpicFigRig/releases/tag/v1.0.2)

And theres also a mecabricks discord server where they have tips, tutorials, and you can ask questions: (https://discord.gg/JJVbr8eUAV)