tidal perch
start_windows.bat starts the webui after it is installed.
Models can be downloaded in the webui's Model tab.
GGML models should be downloaded manually as many versions are commonly included in the same repo and only one is needed. Models go in: \text-generation-webui\models
Are there any errors shown?
What path are you installing it under? A common cause for those errors is that the path is too long.
Delete the installer_files folder and try to install again. There may have been a network issue when you tried to install the first time.