I have used a free
Dwg block library like this one in the past, but found there can be a load of disadvantages from doing so, especially if you are only just developing your AutoCad skills.
For starters a lot of the stuff on there is way too ornate, and i wouldn't dream of using them on a 'working' drawing.
Some are 2D views of 3D blocks, and depending on how they were set up, they can cause a load of grief when imported into a '2D' drawing (i.e. may not default to be at 0 in your Z plane) which can cause issues with your Snaps like intersection, end point etc and also when adding dimensions/measuring points at a later point.
Also a lot are attributed blocks so if they needed modifying you'd need to use the block editor etc; a simple Explode to modify would leave a load of text all over the show.
Then you might also have issues with layer names. Years ago when i did my AutoCad assignments we were marked on Layer convention/discipline. It's pretty much guaranteed that any blocks you pull from that site will have their own layering names/set-up so you might have to go through the block and 're-layer' everything to your own conventions (There's easy ways/shortcuts around this. i.e. on the older versions of AutoCad there was a command call 'LAYERWALK' but it changed its name on the newer version and i can't remember what the new command is).
In my view, it might be useful for pulling in stuff like toilets, sinks & furniture but for basic stuff like windows, doors & stairs etc i would just draw them from scratch.
Good luck with your project, and using AutoCad 2017 (i used to love using AutoCad until microsoft got their grubby mits on it, and tried to make it look like all their other Office software)
Just out of curiosity, does AutoCad 2017 have an option to default to the old 'Classic' AutoCad mode?