The easiest way to go is doing a full-immersion cold-brew.
- Grab a Mason Jar, Jar, beer bottle, anything.
- Grind your coffee (normally for french press)
- Put natural temperature (24°C) pure water.
- Let it steep at your kitchen or refrigerator (don't move it) for 12-24hrs
- Filter the grounds (metal, paper, sock filter, whatever)
After you done that, start to modify the variables.
For me, works perfectly at natural temperature, 12hrs, v60 grind setting, Chemex filter and a 1:5.5 ratio :)
That gives a concentrate, that I diluted with ice/water until I reach typical 1:15 ratio.
You don't need any fancy equipment. You can even do it in a glass and then filter with a spoon. Like a cold cupping session