Added an introduction to the big Bundle example

input/pagecontent/Bundle-ContinuaBundleWithDevice-intro.md

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+The following example shows a real-life recording of a home monitoring blood pressure measurement. Due to the
+size and complexity of this example, a bit of background and guidance on the contents will be provided
+
+## Background
+
+In many situations citizens may use personal equipment (their own property or borrowed from a healthcare
+provider) to automatically capture and record medical observations. This class of equipment is known by the
+term "Personal Health Devices" (PHDs). A number of challenges arise from the complexity of dealing with
+diverse consumer-grade Internet-connected equipment used under no clinical supervision:
+
+ - Type, quality, accuracy and provenance of the observations?
+ - Systematically recording the state of sensors and relevant events detected during the measurement.
+ - Meta information regarding the equipment, the observation, or the context.
+ - What is the identity of the patient/citizen/user? Authorization, authentication, etc...
+ - Accuracy of timestamps, consistency of timelines etc. In particular when the PHD is used by someone
+   traveling around the globe.
+
+### Standardization and Interoperability
+
+In order to deal with these challenges and coordinate the effort across many different standardization bodies,
+the [Continua Design Guidelines (CDG)](https://www.pchalliance.org/continua-design-guidelines) has been
+created, and the coordination effort continues under the [IHE Personal Connected Health
+(PCH)](https://wiki.ihe.net/index.php/Personal_Connected_Health) program. In 2013, Denmark adopted the CDG
+as a [reference
+architecture](https://sundhedsdatastyrelsen.dk/-/media/sds/filer/rammer-og-retningslinjer/referenceaktitektur-og-it-standarder/referencearkitektur/referencearchitecture-collecting-health-data-citizens.pdf).
+
+The CDG offers guidance to implementors of PHD equipment and related applications, providing a single data
+model that may be expressed and exchanged using (and translated back and forth between) many different
+container formats and transports:
+
+ - [IEEE 11073 PHD](http://11073.org/)
+ - [HL7 FHIR PHD IG](http://hl7.org/fhir/uv/phd/)
+ - [HL7 CDA PHMR](https://www.hl7.org/implement/standards/product_brief.cfm?product_id=33)
+ - HL7 v2 Messaging
+
+With transports ranging from [Bluetooth Low
+Energy](https://www.bluetooth.com/bluetooth-resources/personal-health-devices-transcoding/), NFC, USB,
+Internet, to [XDS.b and XDR exchange of PHMR
+documents](https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-H.813-201911-I!!PDF-E&type=items)
+
+
+
+## Bundle Overview and Reader's Guide
+
+The example provided here is the data payload transferred from the home of the user over the Internet to a
+central collection server at a tele-monitoring service provider. This bundle is a single self-contained
+message, demonstrating how a blood pressure measurement is encoded using a FHIR Bundle compliant to *both* the
+[HL7 FHIR PHD IG](http://hl7.org/fhir/uv/phd/) *and* the `DkCoreObservation` profiles.
+
+### Bundle Structure and Content
+
+The Bundle contains the following entries:
+
+ - **The Patient** As the bundle must be self-contained, a Patient resource must be included. This is of
+   course a `DkCorePatient`.
+ - **The Gateway Device** The blood pressure monitor device used in this case is not aware of the identity of
+   its user. It will just send the measurement using Bluetooth Low Energy to a compliant gateway. The
+   gateway - in this case an Android app - is responsible for adding the identity of the patient, and also for
+   checking (and correcting if necessary) the blood pressure monitor's built-in clock, which is used to create
+   the observation timestamps.
+ - **The PHD** In this case, a blood pressure monitor from A&D was used to create a blood pressure
+   measurement.
+ - **Battery Level Observation** The A&D blood pressure monitor gauges its own battery every time it is used.
+ - **Coincident Timestamp Observation** The Gateway Device reads the clock of the PHD and creates this
+   observation of the *current time* of the PHD timestamped using the Gateway's clock (which is supposed to be
+   synchronized with a time service). This is a way to detect (and possibly correct) breaches in the timeline.
+ - **Blood Pressure Observation** This is a `DkCoreObservation`
+ - **Heart Rate Observation** Also a `DkCoreObservation`
+ - **Blood Pressure Status Observation** This observation type can be used to report a number of conditions
+   during the measurement. In this case, an irregular pulse was detected during the measurement. Some PHDs may
+   be able to report different conditions - e.g. that the blood pressure cuff was too loose.
+
+ You may also notice that the type of the Bundle is a transaction bundle and that all the entries in the
+ bundle are conditional creates using a funny-looking identifier, which is actually the result of a calculated
+ function that summarises the resource into a short form (hash), in order to prevent duplicates.
+
+
+## Narrative Content
+