i guess. im new to this

if i cant do this with extra is there a plugin that makes it so i can?

also i cant get that gimp program to work. i unzipped it and looked through the files and couldnt find setup or install or run or anything. i saw a few reedme files but when i tryed to open them i got a message asking what i would like to open it with and with past experience choosing something only makes it worse. i found out how to use the paint program a little more but my terrain is coming out very jaggid so i want gimp