Thinking about purchasing my first Quad-plex apartment building

[Jonathan Kim]

Hello  BiggerPockets Community...

So I'm at the point where I am now thinking about buying a 4 family house. I purchased the duplex I'm living in now about 3 years ago. Completely run down but one side was in good condition and had a tenant. I gutted and totally renovated the other side I'm living in and saved enough for another decent size investment. I particularly enjoyed the financial bump up you get going with this investment options. Passive income, loving it! 

So in the 3 years I started down this path, I got handy enough to fix general house issues (replaced sump pump and leaky sinks and tubs), manage tenants, lease issues and with an ever realizing thought in my head that real estate is not easy. It needs to be respected and you have to be vigilant or it all can go south on you quick.  

In any case, that's my back story and now to the task at hand...

I'm looking at a Quad apartment building right now and the numbers looks right to me. The condition is okay and the roof is in good condition. I didn't see any signs of water damage or structure problems but I'm not an inspector. I'm thinking of pulling the trigger soon but I needed to consult everyone here on how should I approach this. I need suggestion on how to prepare and things to look out for and more immediately... Should I start a LLC and buy the property under the LLC name?

Thanks in advance for the advice and your time.