new to model building, what program do you suggest I use to make my own buildings using clever textures?

Brent, I am nowhere near a “precision” modeler, but I’ve had fun with Clever Bros “kits” and parts. Your “software” needs will depend on what you want to do. For a kit, you should be able to print out with any fairly recent Microsoft Office or similar package.

To make your own buildings, you could use Clever Bros textures cut to size to fit. Actually, I used an AutoCad program in one case to draw walls, roof, etc., to full scale. But that might be overkill.
Ebenezer Grill – AutoCad plus Weathered Red Clapboard plus store bought windows/doors
http://blacktop-crossing.blogspot.com/2014/12/ebenezer-grill.html

If a Clever Bros “kit” is close but a slight modification is needed, maybe use Paint Shop. I did that to remove windows from a Clever Bros Tool Shop.
Tobacco Barn – Tool Shop, Creeky Roofing plus a little Paint Shop to remove windows.
http://blacktop-crossing.blogspot.com/2015/01/the-baccer-barn.html

No doubt, sooner or later you’ll hear from Paul Egri. He really likes to use Clever Bros textures and kits to then run through Paint Shop for a whole new structure. He helped me with a small building from a photograph I had.
Cotton Broker office – Paul Egri Paint Shop
http://blacktop-crossing.blogspot.com/2016/02/cotton-broker-office.html

I’ve also found that some Clever Bros textures can help extend some realism to structures just by adding a little card stock here and there.
Cotton Gin – cedar shake roofing, old brick, and vertical seam sheet metal from Clever Bros plus lots of wood and miscellaneous parts.
http://blacktop-crossing.blogspot.com/2011/12/cotton-gin.html

These were just some thoughts that crossed my mind. Since you were asking about "what program" I may have missed your question!

Thanks for the plug Mack I am in no way an expert at making paper and card structures Thats what these guys do But I have made some nice structures and a few of them have been posted on the blog page built by Dave Rarig I use nothing more than MS Paint for Windows This is an easy program to learn and a quick way to learn how to import parts into your build The downside to using Paint is the graphics are of lower quality than used by Clever But I find them very acceptable if you do them in the scale you are modeling If you message me in Face Book I will be happy to help you learn how to use Paint

Here are some models I've made. These involve different degrees of bashing kits, rather than scratch-building. In particular, if you compare the Habbaker's Garage with the download kit page, you can see what can be done just by printing out an extra sheet of two and making some careful cuts. http://www.donalbury.com/kitbashing.html

Oh, I almost forget, there is this abandoned project in N-scale with a large warehouse/freight depot made from Clever Models texture sheets. Only the office door and a couple of windows at one corner are from a Clever Models kit. Everything else, such as the freight doors, corner trim, etc. is cut from printed texture sheets. Internal bracing is a mixture of wood and cardstock. http://cedarkeyrr.weebly.com/