hi Bienfechiva.
this is all i could find from the internet.
( Put the eyepiece with the largest number written on it into the focuser. ... Turn the focus knob back and forth slowly until the image is in sharp focus.)
as you say you have the manual so no point it sending you to that link.
so go to this link and see if it helps.
Tasco Galaxsee 46114500 500 114mm Telescope No image through the eyepieces...