hello hello hi hi yes yes thank you for downloading and stuff
today i will be showing you: "hw 2 d0wnl0ad undrgr0nd m0d 2 undrtel"
anyways 2 situations:
1: u buy game (epic)
2: my lawyers have advised me not finish this sentence
either way what you can always do is:
1) open undertale. 
2) open task manager. 
3) right click on undertale in the task manager. 
4) click "open file location". you should be in a kewl folder. nice.
5) extract everything in this archive there. (click yes for replace dialog thingy idk)
6) open the deltapatcher folder you extracted.
7) patch the DATA.WIN file (yes i'm srs rn) using the underground.xdelta file
8) enjojiyiyioyioyioyioyiyjykyjlyhkljhlejlhzljh

thank for watch lik and subcribs or i cri everytim :(