Hi I have bought a nano pi m4 v2 board, I have few questions,

I was going through schematics, and in that I do not see components name or part number written.

1. How I am supposed to learn about a component if there names are not shown?
2. How do I use .dxf files?
3. Why friendlyelec does not explain about built images anywhere, e.g. these are the images in there buildroot.tgz

sd-fuse_rk3399/buildroot: .
├── idbloader.img
├── info.conf
├── kernel.img
├── MiniLoaderAll.bin
├── param4sd.txt
├── parameter.txt
├── partmap.txt
├── resource.img
├── rootfs.img
├── sd-boot
│   ├── param4sd.txt
│   └── partmap.txt
├── trust.img
├── uboot.img
└── userdata.img

What each image do? What is the purpose of
idbloader.img
info.conf
MiniLoaderAll.bin
param4sd.txt
parameter.txt
partmap.txt
resource.img
param4sd.txt
partmap.txt
trust.img
userdata.img

Kindly explain?