VarsityLover

Soo, my sister wanted me to download Technic Platfrom, along with the Technic Launcher. I was new to the launcher but my sister has more experience than me. The problem is was whenever I try to log in, it'll say "INVALID CREDENTIALS. INVALID USERNAME OR PASSWORD" But I put my Minecraft stuff like it told me to like the username and password. It still doesn't work. Can anyone explain on what I'm doing wrong?