I'm new to WordPress and I managed to download one theme but after having changed my mind I decided I would like another one. However when I try and install the theme whilst managing my website it tells me that the themes are broken and 'The parent theme is missing. Please install the "bp-default" parent theme.'. I also tried to install the themes another way by using my the control panel on my domain registration company but neither way works. Could anyone please tell me what I am doing wrong and/or what I need to do to be able to use any other themes. Any help would be appreciated!