great small self relay for starters with no pro-technical skill needed just get windows or linux app run it
note down local ip ws://10.10.10.1:4869 and add the custom relay it to you nostr client app amethyst or self-hosted-webapp that's it. https://image.nostr.build/81a748c6699c351238ad41892b2929c98de49ec245b4535890ccdb4d5f496d44.png 
if you cli tool called "nak" u can post to it and read it for test 
POST PUSH WRITE a note
nak event --sec 9fa4644f91286358f3b79f1e6790b8a3a0ab9fc30f5168f638b7d4552546578 -c 'test it' --auth --pow 3  ws://10.10.10.1:4869
READ a note
nak req -i 09491fa5ff3f50bf4ce384aa87d34160bb1dbf8c6f01e93cb0430eafcdc30d55 ws://10.10.10.1:4869

(above --sec HEX and -i HEX are fake use ur own)