I suggest you get spin training with an instructor. That is what I did.
I then was able to go out and spin my airplane by myself without
mishap. I would not recommend you teaching yourself how to spin in your
Cessna 150 without someone else along who can get you out of trouble.
It could be fatal if you get disoriented. For most people, spins are
scary at first. Panic can set in. Just the comfort of having an
instructor along will give the confidence needed to successfully and
without fear complete the manuever. Once you have recovered from
several spins, you should be in good shape to do it on your own.

As for the paperwork entries in your logbook. What I do is have them
give me the sticker with work description. I then put it, by itself, in
an 8x10 folder, on it's own sheet of paper in a glassene envelope. All
nice and neat, and if mistakes are found later on, they can be fixed
without making a mess. This is the best way to keep a logbook that
results in a neat, readable, sequential logbook that has no mistakes or
messes in it. It is a flexible system that will stand the test of
time. I never let any mechanic put anything in my logbooks. They all
do it differently and it's a guaranteed mess.