親しみやすい is one word, meaning amicable, friendly, approachable.
It comes from verb 親しむ + adjective やすい(易い).
There are many other words with ~やすい.
やすい means easy (to ~), 親しむ is to get familiar to, acquainted with.
So 親しみやすい = easy to get familiar with/acquainted with.
~っす is a slangish expression for ~です.