Okeydokey, a bit at a time!
Strimmer wise (actually it's a brushcutter....genuine strimmers have a curved shaft and a flexible drive shaft cable. (I know this is a combi tool though).
Take the allen screw out, and see if the drive shaft is actually spinning. These machines have a centrifugal clutch so the engine has to be running reasonably fast for this to happen.
At the same time, see that the drive shaft is long enough to engage with the strimmer head......is it a Stihl one? Also check that when you manually turn the head, the part that engages with the drive shaft is turning too.
To expose the strimmer line, squeeze the white lugs inwards to release the spool outer cover.
The blower ( an elderly BG 55 or something?)
If both ends of the spring are whole, you'll need to rewind the spring into a tight coil and then engage it in the recoil unit....that's on the plastic cover, not the engine. You can then engage the starting pawl and it's retaining spring.
Forget about the starting rope for now - that can be rewound after....the rope sits in that notch as you wind the unit to tension the spring.
Horrible jobs I agree but we've all been there!
Maybe the springs are available in a pre wound cassette - I don't know.
Have fun!
John