@dantheman36801 the reason for not having a guide, is because nobody has made one yet. Those guides are commonly created by users like you and I and not the iFixit staff.
As for your UE Boom 3 not coming on, you will have to take it apart and check the charge connector. You'll have to measure the voltages on the board once you connect your charger. Of course, you made sure that your charger and charge cable are working properly and do not have any bend broken or corroded pins etc.
To take it apart use videos [https://www.youtube.com/watch?v=0-R46ZLkiMk|like this] ***++++***Once you are in it, post some goo pictures of all of your circuit boards. That way we can see what you see and hopefully help you further.
While you work on your speaker, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
Repair is War on Entropy!