1.Download Optifne,Shader Mod,Liteloader and Voxelmap (link in description)
2.Start the Optifine .exe and click install
3.click on the shader installer and klick on seelect base version and chose the 1.8 optifine version and klick on ok
4.open litelauncher and select extend from,and chose the version 1.8 optifine and shaders bla bla bla, and click ok
5.now start Minecraft and selcet the right profile
6.then minecraft started click close minecraft and make Windowsbutton + r and make %appdata% and go in the .Minecraft folder
7.then you having the folder mods go in then and open in it 1.8
8.now copy and paste the voxelmap in

The Video have Video errors but its enough