How should I go about writing up a lease or should I use the BP 1

[Steven Sestir]

Hello everybody,

   I just bought a duplex in Upstate New York, and I was going to use the following landlords lease but they did not have one for five year.  I just learn about this a few weeks days ago.  I do have a tenant in the other side of the duplex and they did pay this weeks month already.  I want to write up a lease to keep myself safe, when and if they move out.  I do not what to have to try to take money out of their security deposit without having a lease if something is broken because I believe that would be illegal.  How would I go about making a proper lease should I call up a law to help or show I just write one up myself or just use the bigger pockets lease and fix some of the wording around for NYS lease? 

Thank you