Need help with spf on exim

Hi everyone,
I need some help with implementing spf on exim.
The spf ACL on the SPF site has a couple of things in it that I do not
understand.
One is this here:

4. Run spfd -path=/tmp/spfd as the same user as Exim runs

Does this mean the deamon needs to run all the time for this to work?

Then the ACL further down recommends this:

5. Now you can use the test on your RCPT/MAIL ACL this way:
#
#    deny    !acl        = spf_rcpt_acl
#
#    And on your DATA ACL:
#
#    deny    senders     = :
#            !acl        = spf_from_acl
#
#    now acl_m8 will hold 'pass','fail', 'unknown', ...
#    so you can take other decisions based on the result
#    like being more strict on some circumstances:
#
#    deny     senders     = :
#             condition   = ${if eq {$acl_m8}{softfail}{yes}{no}}
#             message     = Not authorized by SPF

What does this mean. What happens if I do not add this to the exim.conf?

Can anyone shed more light onto this? It seems ruther cumbersome to
implement this in Exim!

thanks