D-Siick

The second method (shift + u) worked great. Thanks for the help!

Hello TDM community, new member and first time posting here. So, I'm currently working on my first fan mission and I require some help. What I'm trying to do is to create an upstairs floor in my mission but I don't know how to delete the specific piece (which is presented in the screenshot which I have attached below). Basically I'm trying to remove the part which is highlighted by the overlapping texture. I've already looked at the tutorial presented in the official TDM wiki but it still doesn't make a lot of sense to me of how to make use of the included "Clipper" tool (if that's what I have to use...). Any help would be appreciated. Thanks in advance!