OBT Forum

I'd say it depends

If it's constructed in parts the assembled in space which I'd assume would be the easiest I'd probably say a year or so.  All they would be doing is bolting the parts together in space

Making it fully operational and fitting it out maybe another 6 months to year depending on the requirements

If it was being built in situ the I think it'd probably take longer as they'd have to ship parts to it before work could proceed

A shipyard as Abele said first they may have to secure a slip to build it and you'd bd limited to jump boom equipped stations

Me personally if I was doing it I'd task 3 enclaves on different planets to build sections of it and transfer by cargo DropShip.  That way your parts can be built in a shirt sleeve environment and in manageable way.  They then get shipped to the station assembly area and put together.  A bit like modern ship construction.

This way you eliminate the risk of building it all in front of everyone and you save yourself trouble if one enclave falls the other two can carry the work.