1. Download the tools - all open source and free, all tools can just be unzip and copy&pasted - even the watcom exe

uasm: http://www.terraspace.co.uk/uasm.html
-> http://www.terraspace.co.uk/uasm252_x64.zip
just unzip - no installation needed

openwatcom v2: https://github.com/open-watcom/open-watcom-v2/releases 
-> https://github.com/open-watcom/open-watcom-v2/releases/download/Current-build/open-watcom-2_0-c-win-x64.exe
just unzip the exe - no installation needed

unilink: ftp://ftp.styx.cabel.net/pub/UniLink (use ftp client to download - most web-browser just stopped doing anything with ftp) 
-> ftp://ftp.styx.cabel.net/pub/UniLink/ulnb0101.zip (there is always only the latest version available named ulnb*.zip)
just unzip - no installation needed

2. unpack and copy the folders into the tools folder

rename the folder to match this hierarchy, no moving of single files - just the complete
folder - in the end these executables need to be reachable

tools\uasm_x64\uasm64.exe
tools\open-watcom-2_0-c-win-x64\binnt64\wpp.exe
tools\ulink\ulink.exe

3. make ulink work: 
outcomment or remove line 3 in tools\ulink\ulink.cfg  "!--remove this line--!" to activate the linker
