Follow the good advice given above, at first I thought you were refering to chinq, and gave you info on that vehicle, sorry much more experienced people than me on the Sie S that can help you, still 1-6 info should be ok.
1.Inspect the hoses going to the rad for the type of retaining clips used, if they are factory fitted get the correct size jubilee clips.
2. Make sure you have enough antifreez and a bole if you intend to reuse what you have especially if it is recent.
3. Disconnect the bottom hose to release the water (not while hot).
4. Remove the other hose.
5. Find the bleed valve that pokes out behind the drivers headlamp, attach a meter or so of string; this will aide you to follow the path of the bleed pipe on refitting.
6. Remove the wireing clip from the rad temp sensor (half way down the right side) Remove the plug going to the fan.
If there is anything I have left out, or got wrong, then someone will be along with extra info.