Washington Eviction help

[Alex Gordon]

It's time to do my first eviction!  I purchased my second property in August, so I have inherited tenants and the old landlords lease.  Tennant has not made February payment and has now stopped responding.  I posted a 14 day pay or quit notice on the door and need to move on to eviction. 

I am a DIY guy and am fairly fluent in leagalese but have not done an eviction before.  Is it possible to represent and file the unlawful detainer yourself?  What documentation or forms do I need?  What happens if they pay after I file?  Can I hold them liable for court fees? 

Those who hire an attorney, what do they charge?  Any other tips?  Thanks!