just before starting the enumration : \setitemize[0]{leftmargin=500pt,itemindent=0pt,labelwidth=10pt} (for bullets) and for numbers : \setenumerate[0]{leftmargin=XXpt,itemindent=XXpt,labelwidth=XXpt}
Put "\Appendix" into ERT code line (which is created using Ctrl + L) And keep creating sections using the section, subsection menu that will keep appearing into the pdf, dvi file as Appendix A, Appendix B and so on.