To install spk, untar the source archive and cd into the spk-version directory that is created. Then execute

 ./configure &&
 make &&
 sudo make install

(The last line can be just make install if executed as root.)

You can use the --prefix configure flag if you don't want to install in /usr/local. I typically install spk like this:

 ./configure \
   --prefix=/usr \
   --sysconfdir=/etc \
   --localstatedir=/var/lib &&
 make &&
 sudo make install

spk.conf will be put in /etc, and when the repository is created it will then reside in /var/lib/spk. After installing spk you may want to have a look at spk.conf and adjust it if you'd like to. (It allows you to ignore certain directories when recording changes to the file system.)