This info is for s10 pick-up, 2wd. The following procedure requires the use of ball joint remover/installer set and a ball joint separator tool or equivalent.
Raise and safely support the vehicle under the frame so the control arms hang free. Remove the tire and wheel assembly. Position floor jack under the spring seat of lower control arm, then raise the jack to support the arm. The floor jack must remain under the lower control arm, during the removal and installation procedures, to retain the arm and spring position. Make sure the jack is positioned securely and will not slip or release during procedure, you could get hurt. Remove the brake caliper and support it aside using a hanger or wire. Make sure the brake line is not in a bind. Remove and discard the lower ball joint cotter pin, then remove the stud nut. Use a ball joint separator to drive the lower joint from steering knuckle. Carefully guide the lower control arm out of the opening in the splash shield using a putty knife. Position a block of wood between the frame and upper control arm to keep the knuckle out of the way.
That should get you started. Safety is your responsibility.