they're pressure feeds really, rather than vacuum, but anyway....

you connect the one on the compressor housing (sorry if this is patronising, but thats the silver aluminium 'snail' on the turbo) directly to the one on the actuator.

this will give you a basic form of boost control, depending on the spring rate inside the actuator, and the pre-load on it (how much you've tightened the rod between the actuator and the wastegate).

how it works is that when you get pressure in the compressor housing (positive boost pressure) this will push on the diaphragm in the actuator. when you get enough pressure to overcome the spring and the pre-load, the rod will start to move and open the wastegate. this makes more air bypass the turbine side of the turbo and keeps the speed down so that it produces less boost. you then have a closed loop system.

be aware that you should first attach the actuator rod to the wastegate with the minimum pre-load possible, that is 3mm. that means that the rod will not fit over the wastegate spindle by 3mm and you'll have to pull it on against the load of the spring. this will give you minimum possible boost so that you can check it and increase it if possible/necessary. depending on the actuator used, your boost may even be too high even at minimum pre-load, and you may have to change to a weaker actuator (for example, a -31 actuator is weaker than a -34).

some systems run a bleed off, either via a mechanical bleed valve, or an electronic one. this is to make it easily adjustable, to reduce the effect of a too strong actuator, or to give the ecu some control over the boost level.

hth.