What is macro's.asm? You probably saw this filename a few times earlier in this help file.
The 'macro's.asm' file is delivered with CA3 and has all kinds of standard defines and labels in it... With this macro's.asm file you can e.g. call any bios call (MSX1 or MSX2) and easily access the BDOS routines. It also has some macro's defined, stuff like setting palettes, copying ram to vram, setting VRAM pages, reading sectors from disk etc. etc.
You should really take a look at this file. This file also is BY DEFAULT included in a new source file. TeddyWareZ used it in all their products and it just is really comfortable. Also you can update this file just to let it fit your needs. This file really is the basis of a new file.