Im new to hammer, and the first time i loaded in a project all the textures went away and left just these static boxes, heres a link to a screenshot (i dont have good screenshot software) https://i.gyazo.com/adecd6531be676e6d23efd7576f90d41.png
that looks like you're in wireframe view - press the camera button at the top left and choose 'textured' or 'shaded textured'