As can be seen in the build instructions, since everything I designed and coded is open source, it is easy to get shel°F setup and running in no time. But during the build process I experienced a few difficulties that I thought would be useful to share:

• The Si7021 sensor comes in a tiny hard to solder package. A heat gun could be used to put it down and make things easier but it could tamper with the sensor according o the datasheet. My solution was to put a little bit of solder on the center pad and slide the sensor into position making sure it is connected to the center and not moving. Then, heating the sides of each pin on the chip and the pad, you add a little bit of solder to create the connection.
  
• The Si7021 has a sticker on the top that needs to be keep on particles that could make the sensor malfunction. I accidentally removed the sticker on one of my sensors at the start and the readings were pretty much the same as a sensor with the sticker. That said in the long run things will probably become more inconsistent so since there is no harm, keep the sticker.
  
• The book is pretty simple to hollow out if you follow the link to the instructions closely. One thing to note is that if you cut out the top of the book to make the sensor pop out it is best if that is not the only way the heat from the board can go. To prevent the creation of a chimney, you can either block the exit by not cutting out the edge and having the sensor slide out through a small opening or you can create another larger chimney on the side or bottom. I didn't do either and the results have been fine, but it doesn't hurt to make the design more robust.