The big thing you'll want to do is download the mods you want to install manually, including BGT Fixpack and BGT Language Pack (I use English, but there are others.) These can be a pain to find on your own, so I will link them from the SHS site.
http://www.shsforums.net/files/file/521-big-world-fixpack/
http://www.shsforums.net/files/file/534-big-world-english/
Here is the most important step I have found for a manual install. Download all the mods you want, unpack them into the Baldurs Gate II Enhanced Edition folder, and then run these files. If you don't, it is possible compatibility with a number of mods will be an issue .
My install spreadsheet is attached. They are grouped according to a recommended install order based on my experience and what I have read. You'll notice it's mainly Baldurs gate 2 mods, so I have little experience with anything for BG1. However, I assume the install order is very similar.
If anyone feels this can be improved please let me know. I know things change and need to be altered
Also, if this is way too confusing I completely understand. If you want, you can try Project Infinity by ALIENQuake. Not something I need to use, but may be up your alley:
https://github.com/ALIENQuake/ProjectInfinity
Hope this helps
BG2 EE Organizer Recent-1.xlsx