Purchasing an Espruino, some questions

There are Solderless Headers on the market, but to get them properly done is imo more difficult than to do some beginner soldering. Whole diameter and pin thickness have to be right for each other. I would go for the soldering, and it does not really matter what you choose... Get an electronics soldering iron with a fine tip and solder with core and do some soldering practice on a paper PCB with some wires... after that, you are just fine to put headers on Espruino with success. Youtube has also great clips where the you can see and get explained how to do it... search for, for example, "soldering tutorial", aor "soldering headers", etc. Whether male pins sticking upwards or downwards or female headers are mounted from the top, it mostly preferences and how you want to use it... Espruino has not only on the edge pins, therefore direct plug-in to bread board has limited applicability... therefore, mount male of female headers from the top and use the wires as described by @DrAzzy to go to the breadboard where you have your other components.