Selling to Inside Sales

Hey everyone!

My target market is fairly niche - Inside sales at HVAC, Plumbing, Electrical, etc. distributors/ GCs. Basically anyone who deals with managing suppliers and RFQs.

I am fairly new to sales so I guess my question is - How do you sell to people who do sales? Where do these guys live, what channels do they respond to best?

What is the best way to start relationships in a relationship based industry for someone new to the game?

Any and all advice is appreciated!