downloaded the mod 2 days ago and wanted to try but I do not seem to see it anywhere. Not in crafting or research. Do I have to spawn it somehow or is it in a different tab of game?

It is in the "Logistics" tab and requires "Electronics" technology to be researched.

I have the electronics researched prior to installing the mod.
Does it have to be a new game to have the distribution center available?

I've made a fresh vanilla save with researched technology and installed the mod - the recipe was available.
Try enter this into the console: /c game.player.force.recipes["sdc-dc-small"].enabled = true