After importing a new kit, if you hit render and see that the models look grey, or untextured, here are a few things you can check:
Check your render engine to make sure that you are using the same render engine as the kit you have downloaded. For instance, if you have downloaded a Maya/Redshift file but are trying to use Maya/VRay, the shaders will not appear correctly, and you will have to redownload the correct version of the kit.
Make sure that your texture maps are set to the correct paths. For information on how to do this, check out our article on How to Relink Textures .
If you are not using a render engine that we currently support, you'll have to check the documentation of that render engine to see how to rebuild materials properly. For information on which softwares and render engine we support, check out article on What 3D software / Render engines do your models work in?