I need to replace the ink... I don't know how to get the cartridge holder into position to put the cartriges in... NX400

Here is a link to the owner manual, which will answer your queston: Epson Stylus NX400, Overview - Technical Support - Epson America, Inc. (http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_UseBVCookie=yes&oid=106004&infoType=Overview)