Start with BiggerPockets Ultimate Beginners Guide (free).

Knowing who you plan to serve can guide you to what you should consider buying.

As a newbie, I need someone to guide me from the beginning to try to avoid mistakes and hopefully be very successful.

A good way to get an understanding of how to get into STR is :STRATEGY: Start Up Guide to Short Term Rental Investing 

Would love to hear what’s guiding your decision-making!

I like the Unofficial Guide to Real Estate Investing.

As others have stated, your fit & finish goals should be guided by whether you plan to:1) Rent: tenants don't always take care of a property, so you want to use lower-grade materials and workmanship.2) Flip: higher quality on workmanship and materials is usually required.Regardless, you always want to "Maintain to the Neighborhood".

They can evaluate your specific case and guide you through the process effectively

Pretty much the core of the STR business.Higher your rank gets, you can increase your price and be more picky in selecting customers which usually lead to a better review / less party or complaints / less expense and higher profit with a happy life.I know some people will argue, but the ranking system is the truth and should be the only guide to your STR journey. 

Hope someone expert in Real Estate can guide me1)Who act like qualified intermediary?