That chart is the final approach chart for 9L at Heathrow. the hold you have circled is that used in the event of radio failure on the approach, and is not used in the normal course of events.
'SIDs' are Standard Instrument Departures, and consist of horizontal and vertical routings and speed instructions after departure from an airport up to the point of the first en-route fix after passing Transition Altitude. These routings are given names, usually related to the name of that en-route fix, and numbers. In the UK, the number may relate (though indirectly) to the runway of departure; in the US the number normally represents the revision state of the procedure. SIDs in the US may also include various 'transitions', which are the onward routings from the first en-route fix to a variety of further waypoints. As an example, yesterday I flew the 'Newark 7' departure from 22R at KEWR, using the 'Merit transition'. The 'Newark 7' SID covers all runways at KEWR, and is the 7th iteration of this procedure. The 'Merit Transition' describes the routing to the Merit fix, which was the first on our homeward route.
'STARs' are Standard Instrument Arrival Routes. They describe the routings and speeds from cruise altitude and various arrival directions to the Initial Approach fix, which in UK will be a hold normally based on a VOR/DME. There may be several intermediate holds described in the procedure, which can be used in the event of heavy traffic. On my arrival at Heathrow from Newark I used the 'Bovingdon 3A' arrival, which routed me from Honiley via several intermediate points to the arrival hold at Bovingdon (BNN) VOR at FL70. That is the end of the STAR. From there, either Radar Vectors or 'Area Navigation' routings (GPS) are followed to the final approach procedure; in my case, the ILS on 27R.
SIDS and STARS are used to give pilots a clue about their routings; they are not a solemn declaration of what will actually occur. Air Traffic can at any time vary the route of flight, altitude and speed at their discretion. As an example, on my BNN 3A yesterday, we did not actually cross any of the beacons or waypoints described on the STAR!
If you have a look on the websites of the various in-flight documentation providers (Jeppesen, Aerad, etc) you may find more information. Alternatively, try Googling 'SID/STAR Tutorial' and see what comes up. Please note: the conventions of symbology used on SID and STAR charts may be different with different publishers. It's vital you obtain the chart key for the publisher of the charts you're using to fully understand what information's presented to you.
Scroggs