Well you've certainly got your work cut out for you if you've never done something like this before.

First - sales is a very viable option here. Since you're working with businesses who tend to high average order values (AOV) you can justify the cost of spending time hand holding potential clients to make sales.

You'll probably want to build a website and either optimize it for search engine optimization (SEO) or use content marketing to attract traffic. If you can give customers a free catalog or other sort of incentive in exchange for their email addresses you have the start of a lead generation process. You can then take those leads and contact them to get them to commit to buying.

If you have high enough margins on your items you could run pay per click (PPC) advertising for your keywords. Although if you don't know what you're doing you could blow your ad budget pretty quickly.

If you haven't done anything like this before I suggest first seeing if you can even get traction on your website. If you can't get that it's unlikely you'll be able to have enough contacts for the sales process.

I hope that helps! :)