First thought that comes to mind is replace the battery.

Second thought (if you want to test things) is to leave the battery in the
box over night with one cable disconnected. See if the battery is dead in
the AM.

a- battery dead, you know the battery is the problem.
b - battery starts truck, you know that something int he truck is draining
the battery.

Third thought, clean the battery terminals. The screw things int he middle,
push them out of th eplastic cable ends, and wire brush the screw things. In
addition to the ends of the cable, and wire brush the round lead contacts at
the side of the battery.

my blazer does not start i had the battery tested and it was a bit
drainded but it was good.. had it fully recharged and still would not
start... tried the next morning and every thing was dead no lights no
clickikng no nothing

Your battery is garbage. Replace it.

Bad battery.